Definitions

1444 of 1444 terms

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.dmg: A macOS disk image used to distribute apps; it mounts like a drive.; IT Applications
@mention: Tagging a person in a message or comment so they are notified.; Business Productivity Software
/dev/null: A device file that discards anything written to it; Linux Foundations
/etc/passwd: The account list: name, UID, GID, home and shell; Linux Foundations
/etc/shadow: The Linux file holding password hashes, readable only by root.; IT Applications Linux Foundations
/etc/skel: Template files copied into new home directories; Linux Foundations
/tmp and /var/tmp: Shared temporary directories; /var/tmp survives reboots; Linux Foundations
3-2-1 backup rule: Three copies of data, on two kinds of media, with one off-site or offline.; Introduction to IT
3-2-1 rule: Three copies of data, on two types of media, with one copy offsite.; IT Applications Network and Security - Foundations
5 Whys: Repeatedly asking why to move from symptom to root cause.; Problem Solving for Technology Business Problems
5W2H: Who, what, where, when, why, how, how much: a completeness check for a problem.; Problem Solving for Technology Business Problems
7 Rs: The seven migration strategies: retire, retain, rehost, relocate, repurchase, replatform, refactor.; Cloud Foundations Cloud Strategy
802.1X: Port-based network access control that requires a login before access; Network and Security - Foundations Networks

A

A3: Lean one-page problem-solving report.; Problem Solving for Technology Business Problems
AAA: Authentication, authorization and accounting: who you are, what you may do, and a record of what you did.; IT Foundations Network and Security - Foundations Network and Security - Applications
Absolute path: A path that starts at / and works from anywhere; Linux Foundations
Absolute reference: A reference that stays fixed when copied, such as $A$1.; Fundamentals of Spreadsheets and Data Presentations
Acceptable use policy: The rules for how staff may use company systems.; Network and Security - Applications
Acceptable use policy (AUP): Rules for how company technology may and may not be used.; Business Productivity Software
Acceptance criteria: Testable conditions a specific story must meet to be accepted.; Agile Methodology
Access control vestibule: A two-door entry where only one door opens at a time, used to stop tailgating.; IT Applications Network and Security - Applications
Accessibility Checker: A Microsoft 365 tool that finds content people with disabilities may find hard to use.; Business Productivity Software
Accounting format: Currency format with symbols aligned at the cell edge, dashes for zeros and parentheses for negatives.; Fundamentals of Spreadsheets and Data Presentations
Accrual basis: Recording revenue and expense when earned or incurred, regardless of cash timing.; Financial Planning for IT Professionals
Accumulator: Variable updated each pass (count, total, best).; Foundations of Programming (Python)
ACID: Atomicity, consistency, isolation, durability: the guarantees a transaction provides.; Data Management - Foundations
ACL: Access control list: ordered permit and deny rules, ending in an implicit deny.; Networks
ACM Code of Ethics: The Association for Computing Machinery's code for computing professionals, adopted 2018.; Information Technology Management and Leadership
Action item: A task agreed in a meeting, with an owner and a due date.; Business Productivity Software
Action title: A slide title written as a full sentence that states the slide's message.; Business Productivity Software Digital Transformation in the Enterprise
Active stylus: A powered stylus with pressure sensitivity that must be charged and often paired.; IT Foundations
Active voice: Subject performs the action: "IT replaced the switch."; Technical Communication
Adaptive challenge: A problem requiring people to change beliefs and behavior, not just apply expertise.; Leading a Technology Transformation
Address pool exhaustion: A DHCP scope with no free addresses left to hand out.; Networks
ADKAR: Prosci's individual change model: Awareness, Desire, Knowledge, Ability, Reinforcement.; Agile Processes and Culture in Technology Cybersecurity Strategy
ADKAR barrier point: The first ADKAR element scored 3 or lower; where change interventions start.; Leading a Technology Transformation
Administrative distance: A ranking of how trusted a route source is; lower wins when sources offer the same prefix.; Networks
Administrative, technical and physical controls: Policies and training; technology that enforces security; and barriers that protect places and equipment.; Introduction to IT
After-action report: Record of exercise or incident findings with owners and due dates.; Risk Management and Information Technology
Aggregate function: A function such as COUNT, SUM or AVG that summarizes many rows.; Data Management - Foundations Data Management - Applications
Agile: An approach that delivers software in short cycles with frequent feedback and room for change.; Introduction to IT Agile Methodology
Agile Manifesto: The 2001 statement of four values and twelve principles behind agile software development.; Agile Methodology
Agile Release Train (ART): SAFe's long-lived team of agile teams, 50–125 people, planning together each Planning Interval.; Agile Processes and Culture in Technology
AI assistant: A built-in AI feature that drafts, summarizes or suggests content.; Business Productivity Software
AI center of excellence (CoE): A central team that sets standards, builds shared platforms and supports AI delivery.; Data and AI Strategy
AIMS: AI management system, the subject of ISO/IEC 42001.; Data and AI Strategy
Air gap: Physical separation of a network from all others.; Network and Security - Applications
Airplane mode: A setting that turns off all radios; Wi-Fi and Bluetooth can be re-enabled separately.; IT Foundations
ALE: Annualized loss expectancy = single loss expectancy × annual rate of occurrence.; Financial Planning for IT Professionals Risk Management and Information Technology Cybersecurity Strategy
Algorithm: A step-by-step procedure for solving a problem or completing a task.; Introduction to IT
Algorithmic bias: Systematically unfair outcomes from a model or automated decision.; Information Technology Management and Leadership
Alias: A temporary name for a column or table, given with AS.; Data Management - Foundations Foundations of Programming (Python)
Allocation key: The driver used to split a shared cost, such as users, tickets or GB.; Financial Planning for IT Professionals
ALTER TABLE: DDL statement that changes an existing table's structure.; Data Management - Foundations Data Management - Applications
Alternative text (alt text): A text description of an image for people who cannot see it.; Business Productivity Software
Amazon CloudFront: AWS's content delivery network, using edge locations.; Cloud Foundations
AMI: Amazon Machine Image: the template an instance boots from.; Cloud Foundations
Amortization: The same allocation for intangible assets, such as capitalized software.; Financial Planning for IT Professionals
Anchor: ^ or $, which tie a match to the start or end of a line; Linux Foundations
Android safe mode: A startup mode that runs only preinstalled apps, used to find a problem app.; IT Applications
Annualized loss expectancy (ALE): SLE times ARO: the expected yearly loss.; Network and Security - Applications
Annualized rate of occurrence (ARO): How many times a year an event is expected.; Network and Security - Applications
Anti-affinity: Rule that keeps VMs or containers on separate hosts.; Cloud Applications
Anycast: One address shared by several devices; the network delivers traffic to the nearest one.; Networks
APIPA: Automatic Private IP Addressing: a 169.254.x.x address a device gives itself when DHCP fails.; IT Foundations IT Applications Network and Security - Foundations+1
Application allow list: Only approved software is permitted to run.; Network and Security - Applications
Application rationalization: Reviewing the application portfolio to keep, invest, migrate or retire each application.; Financial Planning for IT Professionals
Application software: Software that performs a task for a person, such as email or accounting.; Introduction to IT
Application spoofing: A malicious app disguised as a well-known legitimate app.; IT Applications
apropos: Searching man page descriptions by keyword (man -k); Linux Foundations
APT: Advanced persistent threat: a skilled, well-funded actor that stays hidden in a network for a long time.; Network and Security - Applications
Archive: One file that holds many files and directories; Linux Foundations
argparse: Standard module for command-line options.; Python for IT Automation
Argument: A value or range a function works on, given inside its parentheses.; Fundamentals of Spreadsheets and Data Presentations Linux Foundations
Arithmetic logic unit (ALU): The part of the CPU that does arithmetic and logical comparisons.; Introduction to IT
ARO: Annualized rate of occurrence: expected events per year.; Risk Management and Information Technology
ARP: The protocol that finds the MAC address for an IPv4 address on the local network; Network and Security - Foundations
ARP poisoning: Sending fake ARP replies to redirect local traffic; Network and Security - Foundations Networks
Aspect ratio: Width to height ratio of the image, such as 1:1 or 16:9.; Practical Applications of Prompt
assert: Raises AssertionError when its condition is False.; Foundations of Programming (Python)
Assertion-evidence slide: Sentence headline stating a claim, with a visual as evidence.; Technical Communication
Asset inventory: A current list of hardware, software and data with owners and classifications.; Network and Security - Applications
Associative entity: An entity that represents a many-to-many relationship, often with its own attributes.; Data Management - Foundations
Associative table: A table that implements a many-to-many relationship.; Data Management - Applications
Assumption log: Record of assumptions and constraints, started at initiation and updated throughout.; Project Management
Asymmetric encryption: A public and private key pair; Network and Security - Foundations Network and Security - Applications
Asynchronous communication: Communication people answer when they can, such as email or document comments.; Business Productivity Software
ATO: Authorization to operate: a senior official's formal acceptance of a system's residual risk under the RMF.; Risk Management and Information Technology
Attack surface: All the points where an attacker could try to get in.; Introduction to IT Network and Security - Applications
Attenuation: Loss of signal strength over distance.; Networks
Attestation: A formal confirmation that controls or requirements are met.; Network and Security - Applications Network and Security - Applications
Attribute: The formal name for a column.; Data Management - Foundations
ATX: The standard full-size motherboard and power supply form factor.; IT Foundations
Audience analysis: Identifying readers' roles, knowledge, needs and attitudes before writing.; Technical Communication
Audit committee: A board committee that oversees audits and internal controls.; Network and Security - Applications
AUP: Acceptable use policy: rules for using an organization's technology.; IT Applications
authorized_keys: The server file listing public keys allowed to log in to an account; Linux Foundations
Auto Scaling: Automatically adjusting the number of instances to match demand.; Cloud Foundations
AUTO_INCREMENT: MySQL column option that assigns the next number to each new row.; Data Management - Foundations
Autocommit: MySQL's default mode, in which each statement is committed as soon as it succeeds.; Data Management - Foundations Data Management - Applications
AutoRun: A Windows feature that can start programs automatically from inserted media; disabled for security.; IT Applications
AutoSum: A command that inserts a SUM formula with a guessed range.; Fundamentals of Spreadsheets and Data Presentations
Availability Zone: One or more data centers with redundant power and networking, isolated from other AZs.; Cloud Foundations
AWS Artifact: Self-service access to AWS compliance reports and agreements.; Cloud Foundations
AWS CAF: AWS Cloud Adoption Framework: guidance for cloud adoption organized into six perspectives.; Cloud Foundations
AWS CAF perspectives: Business, People, Governance, Platform, Security, Operations: the capability groups a cloud transformation must address.; Cloud Strategy
AWS CloudTrail: Records API calls and account activity for auditing.; Cloud Foundations
AWS Direct Connect: A dedicated private connection from a customer site to AWS.; Cloud Foundations
AWS DMS: A service that migrates databases with minimal downtime by replicating changes until cutover.; Cloud Foundations
AWS Health Dashboard: Shows AWS events and issues that affect your resources.; Cloud Foundations
AWS KMS: The managed service for creating and controlling encryption keys.; Cloud Foundations
AWS Marketplace: A catalog of third-party software and services billed through AWS.; Cloud Foundations
AWS Trusted Advisor: A service that checks an account against best practices in six categories.; Cloud Foundations
AWS Well-Architected Tool: A console service that reviews a workload against the framework and records risks.; Cloud Foundations

B

B-tree index: A multi-level index; the default kind in MySQL.; Data Management - Foundations
BAA: Business associate agreement: HIPAA contract binding a vendor that handles PHI.; Risk Management and Information Technology Cloud Strategy
Backout plan: The tested procedure for undoing a change.; Network and Security - Applications
Balanced scorecard: Kaplan and Norton's four perspectives: financial, customer, internal process, learning and growth.; Technology Governance
Band steering: An AP feature that moves dual-band clients onto 5 or 6 GHz.; Networks
Bandwidth: How much data a connection can move per second, such as 1 Gbps.; Introduction to IT
Baseline: Measurements of normal network behavior used to spot anomalies.; Networks Digital Transformation in the Enterprise
Basic assumptions: Schein's deepest culture level: taken-for-granted beliefs.; Agile Processes and Culture in Technology
Batch processing: Processing records together in groups on a schedule, such as payroll overnight.; Introduction to IT
BCP: The plan for keeping critical business functions running during a disruption; Network and Security - Foundations
BEC: Business email compromise: fraud using a hijacked or spoofed business email account.; IT Applications
Benchmarking: Comparing costs or performance against peers, history or market prices.; Financial Planning for IT Professionals
Benefits realization: Managing a change so its intended benefits are defined, owned, measured and achieved.; Leading a Technology Transformation
BIA: Analysis of which functions matter most and what outages cost; Network and Security - Foundations Risk Management and Information Technology
Big idea: One sentence stating the point and why it matters to the audience.; Digital Transformation in the Enterprise
Biometrics: Identifying a person by a physical trait such as a fingerprint or face.; IT Foundations Network and Security - Foundations
BitLocker: Windows full-volume encryption for fixed drives; BitLocker To Go covers removable drives.; IT Applications
Bitmap index: An index of bits suited to columns with few distinct values.; Data Management - Foundations
Blameless postmortem: A review focused on systems and process, not individual fault.; Problem Solving for Technology Business Problems Agile Processes and Culture in Technology
Block (page): The fixed-size unit in which storage is read and written.; Data Management - Foundations
Block storage: Raw volumes attached to an instance like a disk; Amazon EBS.; Cloud Foundations
Blockchain: A shared, tamper-resistant ledger kept by many parties.; Introduction to IT
BLUF: Bottom line up front: putting the main point or request at the start of a message.; Business Productivity Software Technical Communication
Book value: Cost minus accumulated depreciation.; Financial Planning for IT Professionals
Boot loader: The program, such as GRUB, that starts the operating system; Linux Foundations
Bottleneck: The slowest component on a path, which limits the whole path.; Networks
box-sizing: border-box: Width and height include padding and border.; Web Design Fundamentals
BPDU guard: A switch feature that disables a user-facing port if spanning tree messages arrive on it.; Networks
Branch: Independent line of commits.; Python for IT Automation
Breach notification law: A law requiring organizations to tell people when their personal data is lost, stolen or exposed.; Introduction to IT
Break-glass account: An emergency admin account used only when normal access fails.; Network and Security - Applications
Breakpoint: Line where the debugger pauses.; Foundations of Programming (Python)
Broadcast address: The last address in a subnet, used to reach every host in it; it cannot be assigned to a host.; Networks
Broadcast domain: The set of devices that receive each other's broadcasts; routers separate them; Network and Security - Foundations
Broadcast storm: Broadcast traffic multiplying in a switching loop until the network stops working.; Networks
Browser hijacker: Malware or an extension that changes the browser's home page, search engine, or redirects.; IT Applications
Brute force: A password attack that tries every possible combination of characters.; Introduction to IT
BSOD: Blue screen of death: a Windows stop error that halts the system to prevent damage.; IT Applications
BSSID: The MAC address of one AP radio serving an SSID.; Networks
Bucket: A Planner column that groups related tasks.; Business Productivity Software
Budget at completion (BAC): Total planned budget for the work.; Project Management
Buffer overflow: Writing past the end of a memory area, which can let an attacker run code.; Network and Security - Applications
Build versus buy: The decision between developing custom software and acquiring an existing product or service.; Introduction to IT
Build, buy, borrow: Train current staff, hire, or use contractors or vendors to close a skills gap.; Information Technology Management and Leadership
Builtin: A command built into the shell rather than stored as a separate file; Linux Foundations
Burn-in: A permanent ghost image left by a static picture.; IT Foundations
Burndown chart: A chart of remaining work against time in an iteration or release.; Agile Methodology
Business associate: A vendor that handles health information for a covered entity; Network and Security - Foundations
Business capability map: A hierarchy of what the organization does (e.g., Order Management), used to tie technology to business value.; Leading a Technology Transformation
Business case: A document justifying an investment by costs, benefits, risks and options.; Financial Planning for IT Professionals
Business continuity plan: How critical business functions keep running during a disruption.; Network and Security - Applications
Business continuity plan (BCP): How an organization keeps its business processes running during and after a significant disruption.; Introduction to IT
Business driver: The reason the organization is acting, such as a lease end, growth, cost or risk.; Cloud Strategy
Business email compromise: Fraud that uses a hijacked or spoofed business mailbox, usually to redirect payments.; Network and Security - Applications
Business impact analysis: An assessment of critical functions and the cost and urgency of restoring them.; Network and Security - Applications
Business impact analysis (BIA): Analyzing critical functions and the effect a disruption would have on each.; Introduction to IT
Business intelligence (BI): Tools and practices that turn stored data into reports and dashboards.; Introduction to IT
Business need: A measurable gap between current and desired performance.; Digital Transformation in the Enterprise
Business process: A repeatable set of steps that produces a business result, such as paying an invoice.; Introduction to IT
Business rule: A rule specific to an organization, enforced with constraints.; Data Management - Foundations
Business-IT alignment: Choosing and running technology so that it directly supports the organization's goals.; Introduction to IT Information Technology Management and Leadership
BYOD: Bring your own device: using personal devices for work under company rules.; Business Productivity Software IT Foundations IT Applications
BYOL: Bring your own license: using licenses you already own on cloud resources.; Cloud Foundations
Bytecode: An intermediate form of compiled code that a virtual machine runs, as in Java and C#.; Introduction to IT

C

Call to action: The specific thing you want the reader to do, with a deadline.; Business Productivity Software
CALMS: DevOps lens: culture, automation, lean, measurement, sharing.; Agile Processes and Culture in Technology
Canary account: An account no one should use, so any sign-in triggers an alert.; Network and Security - Applications
Candidate config: Staged change not yet applied.; Python for IT Automation
Candidate key: A minimal set of columns that uniquely identifies rows.; Data Management - Foundations
Capability level: Rating, 0 to 3, of one practice area.; Technology Governance
CapEx: Capital expense: money spent up front on assets such as servers.; Cloud Foundations Financial Planning for IT Professionals
Capex vs opex: Up-front capital purchases depreciated over years, versus operating expenses paid as used.; Cloud Strategy
Capital expense: A large up-front purchase, such as buying servers.; Introduction to IT
Caption: A label under a figure or screenshot that says what it shows.; Business Productivity Software
Capture group: Part of a pattern in parentheses, returned by group(n).; Python for IT Automation
Cardinality: How many instances of one entity can relate to one instance of another.; Data Management - Foundations
Cargo-cult agile: Copying agile rituals without the values that make them work.; Agile Processes and Culture in Technology
Cartesian product: Every row of one table paired with every row of another.; Data Management - Foundations
CASCADE: Referential action that applies a parent's delete or key update to its child rows.; Data Management - Foundations
CASE expression: Returns the value of the first WHEN branch whose condition is true.; Data Management - Applications
Case-sensitive: Treating upper- and lowercase letters as different; Linux Foundations
Cc and Bcc: Copy recipients who are visible (Cc) or hidden from other recipients (Bcc).; Business Productivity Software
CCoE: Cloud Center of Excellence: a cross-functional team that sets cloud standards, runs the platform and guides adoption.; Cloud Strategy
Cell: Block of notebook code run with Shift+Enter.; Foundations of Programming (Python)
Cell reference: A cell's address: column letter plus row number, such as B4.; Fundamentals of Spreadsheets and Data Presentations
Center Across Selection: Centers text over several cells without merging them.; Fundamentals of Spreadsheets and Data Presentations
Centralized IT: One IT department makes most technology decisions for the whole organization.; Introduction to IT
Certifiable: An accredited body can audit and certify an organization against the standard.; Technology Governance
Certificate authority (CA): A trusted party that verifies identities and signs certificates.; Network and Security - Applications
Certificate of destruction: A vendor's signed record that specific drives or devices were destroyed.; IT Applications
Chain of custody: A documented record of everyone who handled evidence, when, and why.; IT Applications Network and Security - Applications Risk Management and Information Technology
Chain-of-thought: Prompting for intermediate reasoning steps before the final answer.; Practical Applications of Prompt
CHANGE: ALTER TABLE clause that renames and redefines a column.; Data Management - Applications
Change advisory board (CAB): The group that reviews and approves normal changes.; IT Applications Networks Network and Security - Applications
Change analysis: Comparing a failing state with a working one to isolate differences.; Problem Solving for Technology Business Problems
Change champion: A respected peer who promotes and supports the change locally.; Digital Transformation in the Enterprise Leading a Technology Transformation
Change enablement: ITIL 4's name for change management: reviewing and scheduling changes so they don't cause outages.; Introduction to IT Technology Governance
Change impact assessment: Analysis of how much each group's processes, systems, roles and skills change.; Leading a Technology Transformation
Change management: Helping people adopt a change through communication, training and support.; Introduction to IT IT Foundations
Change saturation: When the number of concurrent changes exceeds a group's capacity to adopt them.; Leading a Technology Transformation
Change the business (CTB): Spend on growth and transformation.; Financial Planning for IT Professionals
Channel: A space inside a Teams team (or Slack workspace) for one topic or project.; Business Productivity Software
Channel width: How much spectrum one channel uses (20 to 320 MHz); wider is faster but more crowded.; IT Foundations Networks
Chargeback: Billing business units for the IT resources they consume.; Technology Governance Financial Planning for IT Professionals Cloud Strategy
Chart type: The visual form, such as column, line or pie, chosen to fit the question.; Fundamentals of Spreadsheets and Data Presentations
CHECK: Constraint that rejects rows where an expression is false.; Data Management - Foundations
Checkpoint: Hyper-V's name for a snapshot: a saved VM state you can return to.; IT Foundations
chmod: The command that changes permissions; Linux Foundations
chown: The command that changes the owner and group; Linux Foundations
CIA triad: Confidentiality, integrity and availability, the three goals of information security.; Introduction to IT Network and Security - Foundations Networks+1
CIDR: Writing a mask as the number of network bits, such as /24; Network and Security - Foundations Networks
CIO: Chief information officer: the executive who leads IT and aligns it with business strategy.; Introduction to IT
CIS Benchmark: Consensus hardening guide for an OS, service or cloud account.; Cloud Applications
CIS Benchmarks: Free, consensus-based hardening guides for operating systems and applications.; Network and Security - Applications
CISO: Chief information security officer: the executive who leads the security program.; Introduction to IT
Clause: A part of a statement that starts with a keyword, such as WHERE.; Data Management - Foundations
Clean install: Installing an OS on an erased partition, with nothing kept from before.; IT Applications
Client-to-site VPN: An encrypted tunnel from one user's device into the company network.; Networks
Cloud computing: Renting computing resources from a provider over a network, as defined in NIST SP 800-145.; Introduction to IT Cloud Foundations
Cloud instance: A virtual machine rented from a cloud provider; Linux Foundations
CMDB: Configuration management database: a record of IT assets and how they relate to each other.; IT Applications Leading a Technology Transformation
CMOS battery: The coin cell that keeps the real-time clock and firmware settings.; IT Foundations IT Applications
Co-authoring: Several people editing the same cloud file at the same time.; Business Productivity Software
COALESCE: Returns the first non-NULL argument.; Data Management - Applications
COBIT: A framework for IT governance.; Introduction to IT Technology Governance
Cognitive load: Mental effort a team must spend; platforms exist to reduce it.; Agile Processes and Culture in Technology
COGS: Cost of goods sold: direct cost of delivering the product or service.; Financial Planning for IT Professionals
Cold site: An alternate site with space, power and cooling only, ready within weeks.; Introduction to IT Network and Security - Applications
Collision domain: The part of a network where two devices sending at once can collide; each switch port is its own; Network and Security - Foundations
Color gamut: The range of colors a display can reproduce.; IT Foundations
Column alias: A name given to a result column with AS.; Data Management - Applications
Command injection: Extra commands smuggled through shell input.; Python for IT Automation
Command substitution: $(command), which inserts a command's output; Linux Foundations
Commit: Saved snapshot with a message.; Python for IT Automation
COMMIT and ROLLBACK: Statements that make a transaction's changes permanent or undo them.; Data Management - Foundations
Commitment discount: Lower rates in exchange for committed usage or spend (reserved instances, savings plans).; Financial Planning for IT Professionals
Communication plan: Table of audience, message, channel, timing, owner and feedback.; Technical Communication
Community of practice: Cross-team group sharing a craft or discipline.; Agile Processes and Culture in Technology
Compensating control: An alternative control used when the preferred one is not possible; Network and Security - Foundations Network and Security - Applications Technology Governance+1
Compiler: Translates a whole program into machine code before it runs.; Introduction to IT
Compliance: Meeting the laws, regulations, standards and policies that apply; Network and Security - Foundations Technology Governance
Compliance mapping: Linking each regulatory obligation to the controls and evidence that satisfy it.; Risk Management and Information Technology
Component: One of seven building blocks a governance system needs, e.g. processes or culture.; Technology Governance
Composite key: A key made of more than one column.; Data Management - Foundations
Composite SLA: Availability of a system made of several services: multiply for serial dependencies.; Cloud Strategy
Compression: Encoding data so it takes less space; Linux Foundations
Concept drift: Change in the relationship between inputs and the target, so a model's learned pattern no longer holds.; Data and AI Strategy
Conceptual data model: A description of the business's entities, relationships and attributes, independent of any DBMS.; Data Management - Applications
Conceptual design: Modeling the business's data as entities, relationships and attributes, independent of any DBMS.; Data Management - Foundations
Conditional formatting: Formatting applied automatically when a cell meets a rule.; Fundamentals of Spreadsheets and Data Presentations
Confabulation: NIST's term for confidently stated but false content, commonly called hallucination.; Practical Applications of Prompt
Configuration item (CI): Any component tracked in a CMDB, such as a server, application or license.; Information Technology Management and Leadership
Configuration management: Tools that apply the same settings to many systems automatically; Linux Foundations
Conformity assessment: Process showing a high-risk AI system meets the Act's requirements before it is placed on the market.; Data and AI Strategy
Consolidated billing: One bill and combined usage for all accounts in AWS Organizations.; Cloud Foundations
Constraint: A rule limiting the output: length, tone, content, sources.; Practical Applications of Prompt Data Management - Foundations
Container: A packaged application that shares the host's kernel.; IT Foundations Network and Security - Foundations Network and Security - Applications+2
Containment: Stopping an incident from spreading, for example by isolating hosts.; Network and Security - Applications
Context: Background information that shapes an appropriate answer.; Practical Applications of Prompt
Continual improvement register (CIR): A database or document to record and manage improvement ideas through their lifecycle.; Business of IT - Applications
Continuing education: Ongoing learning, often required to keep a certification active.; Introduction to IT
Continuous delivery: Keeping software always in a releasable state through automated build, test and deploy.; Agile Processes and Culture in Technology
Contributing cause: A factor that increased the likelihood or impact but alone did not cause the problem.; Problem Solving for Technology Business Problems
Control unit: The part of the CPU that directs and coordinates each instruction.; Introduction to IT
Conway's law: Organizations design systems that mirror their communication structures.; Agile Processes and Culture in Technology Leading a Technology Transformation
Copyleft: A license that requires derived works to keep the same freedoms; Linux Foundations
Copyright: Legal protection for original works, including software code, against unauthorized copying.; Introduction to IT
Corrective action: Action that removes the root cause of a detected problem.; Problem Solving for Technology Business Problems
Correlated subquery: A subquery that refers to the outer query and runs once per outer row.; Data Management - Applications
Cost allocation tag: A label activated for billing so costs can be grouped by project, team or environment.; Cloud Foundations
Cost of delay: The value lost by delivering an item later.; Agile Methodology
COUNT and COUNTA: COUNT counts numeric cells; COUNTA counts every non-empty cell.; Fundamentals of Spreadsheets and Data Presentations
COUNT(DISTINCT ...): Counts different values, avoiding inflated counts after a join.; Data Management - Applications
COUNTIF, SUMIF, AVERAGEIF: Count, sum or average the cells that meet one condition.; Fundamentals of Spreadsheets and Data Presentations
COUNTIFS, SUMIFS, AVERAGEIFS: The same with several conditions, all of which must be met.; Fundamentals of Spreadsheets and Data Presentations
Covered entity: A health plan, clearinghouse or provider that must follow HIPAA; Network and Security - Foundations
CRC error: A frame whose checksum fails, showing it was corrupted on the way.; Networks
CREATE INDEX: Builds an index on one or more columns to speed up searches.; Data Management - Applications
CREATE OR REPLACE VIEW: Creates a view or redefines an existing one.; Data Management - Applications
CREATE TABLE: DDL statement that defines a new table, its columns, data types and constraints.; Data Management - Foundations
Creative Commons: A family of licenses for open content; Linux Foundations
Credential stuffing: Reusing leaked username and password pairs on other sites; Network and Security - Foundations
Credentialed scan: A vulnerability scan that signs in to the system and sees more detail.; Network and Security - Applications
Criteria: The condition, such as ">=1000" or "West", that decides which cells count.; Fundamentals of Spreadsheets and Data Presentations
Critical path: Longest sequence of activities; sets the project's minimum duration.; Project Management Leading a Technology Transformation
CRL: A CA's published list of revoked certificate serial numbers.; Network and Security - Applications
CRM: Customer relationship management: software that tracks customers, sales and service history.; Introduction to IT
cron: Linux scheduler; five fields: minute, hour, day, month, weekday.; Python for IT Automation
CROSS JOIN: Pairs every row of one table with every row of another.; Data Management - Applications
Cross-site scripting (XSS): Injected script that runs in other users' browsers.; Network and Security - Applications
Crosstalk: Interference between wire pairs in the same cable.; Networks
Crow's foot notation: ER notation that marks cardinality with bars, rings and three-pronged 'feet'.; Data Management - Foundations
Crown jewels: The assets whose loss would most harm the mission: key data, systems and processes.; Cybersecurity Strategy
Cryptographic erase: Sanitizing a drive by destroying the key that encrypts its data.; Network and Security - Applications
CSF Profile: Current or target state of an organization's cybersecurity outcomes against CSF subcategories.; Risk Management and Information Technology
CSF Tier: Rigor of cybersecurity risk governance and management: Partial, Risk Informed, Repeatable, Adaptive.; Risk Management and Information Technology
CSF Tiers: Partial, Risk Informed, Repeatable, Adaptive: rigor of cybersecurity risk governance and management.; Cybersecurity Strategy
CSPM: Cloud security posture management: continuous checking of cloud settings.; Network and Security - Applications Cloud Strategy
CSR: Certificate signing request: the public key and names sent to a CA, signed with the private key.; Network and Security - Applications
CSRF: Cross-site request forgery: making a logged-in user's browser send an unintended request.; Network and Security - Applications
csv.DictReader: Reads CSV rows as dictionaries, handling quoted commas.; Foundations of Programming (Python)
CUEC: Complementary user entity control: a control the customer must operate.; Risk Management and Information Technology
Cumulative flow diagram: A chart of item counts per stage over time; widening bands signal bottlenecks.; Agile Methodology
Current and Target Profile: CSF outcomes achieved today versus outcomes the organization intends to achieve; the gap drives the action plan.; Cybersecurity Strategy
Curse of knowledge: An expert's difficulty imagining what a novice does not know.; Technical Communication
Customer-managed key (CMK): An encryption key the customer creates, rotates and can revoke in the provider's key service.; Cloud Strategy
CVE: Common Vulnerabilities and Exposures: the ID system for publicly known vulnerabilities.; Network and Security - Applications
CVSS: Common Vulnerability Scoring System: a 0.0 to 10.0 severity score.; Network and Security - Applications
Cyber Kill Chain: Lockheed Martin's seven-stage model of an intrusion.; Network and Security - Applications
Cycle count: How many full charge cycles a battery has gone through; capacity falls as it rises.; IT Foundations
Cynefin: Snowden's sense-making framework: clear, complicated, complex, chaotic, confusion.; Agile Processes and Culture in Technology

D

Daemon: A background service process; Linux Foundations
Dashboard: A one-page summary of headline numbers, charts and filters.; Fundamentals of Spreadsheets and Data Presentations
Data at rest, in transit, in use: Stored data, data moving across a network, and data being processed.; Network and Security - Applications
Data bars, color scales, icon sets: Conditional formats that show size, intensity or category inside cells.; Fundamentals of Spreadsheets and Data Presentations
Data cap: The monthly limit on a cellular data plan.; IT Foundations
Data classification: Labeling information by sensitivity, with handling rules for each level.; Business Productivity Software Network and Security - Applications
Data contract: An agreement between data producer and consumer on schema, semantics, quality and SLAs, often enforced in the pipeline.; Data and AI Strategy
Data custodian: The technical role that implements protections for data.; Network and Security - Applications
Data fabric: An architecture that uses metadata and automation to integrate and govern data across distributed sources.; Data and AI Strategy
Data governance: Rules on who owns data and on its quality, privacy, retention and access.; Introduction to IT Data and AI Strategy
Data independence: Physical changes do not change query results.; Data Management - Foundations
Data lake: Stores large amounts of raw data in any format for later analysis.; Introduction to IT
Data loss prevention (DLP): Tools that detect and stop sensitive data from leaving the organization.; IT Applications
Data masking: Hiding part of a value when it is displayed.; Network and Security - Applications
Data minimization: Sharing only the data needed for the task.; Practical Applications of Prompt Information Technology Management and Leadership Data and AI Strategy
Data mirroring: Writing every change to two drives at once (RAID 1) so one can fail safely.; Introduction to IT
Data owner: The accountable business person who sets a dataset's classification and access.; Network and Security - Applications
Data owner and data custodian: The leader accountable for data, and the team that protects it day to day; Network and Security - Foundations
Data product: A dataset published with an owner, documentation, quality SLOs and access interfaces, built for consumers.; Data and AI Strategy
Data profiling: Statistical analysis of a dataset to find nulls, ranges, patterns and anomalies.; Data and AI Strategy
Data quality: How accurate, complete, consistent and current data is.; Introduction to IT
Data series: A set of related values plotted together, such as one region's monthly revenue.; Fundamentals of Spreadsheets and Data Presentations
Data sovereignty: Data is subject to the laws of the country where it is stored.; Network and Security - Applications Cloud Strategy
Data steward: Business role that maintains definitions and quality rules for a data domain.; Data and AI Strategy
Data strategy: A plan linking data management and use to business objectives, with owners, sequencing and measures.; Data and AI Strategy
Data type: The kind of value a column holds, such as INT, DECIMAL, VARCHAR or DATE.; Data Management - Foundations
Data types: The kinds of values a program stores, such as integer, float, string and Boolean.; Introduction to IT
Data validation: Rules that limit what can be entered in cells, such as a drop-down list.; Fundamentals of Spreadsheets and Data Presentations
Data versus information: Data is raw facts; information is data organized to have meaning.; Introduction to IT
Data visualization: Showing data as a chart or graphic so patterns are easy to see.; Business Productivity Software
Data warehouse: A central store of cleaned data from many systems, built for analysis.; Introduction to IT Data Management - Applications
Data-ink: Ink that shows data; maximize it, remove the rest.; Technical Communication
Database: An organized collection of related data.; Data Management - Foundations
Database administrator (DBA): Designs, tunes, secures and backs up databases.; Introduction to IT
Database management system (DBMS): Software that creates, runs, secures and recovers databases.; Data Management - Foundations
Date serial number: How Excel stores a date: the count of days from January 1, 1900.; Fundamentals of Spreadsheets and Data Presentations
DATEDIFF: Number of days between two dates (first minus second).; Data Management - Applications
DBMS: Database management system: software that stores, secures and manages a database.; Introduction to IT
DCAM: Data Management Capability Assessment Model from the EDM Council, common in financial services.; Data and AI Strategy
DDL, DQL, DML, DCL, DTL: The five SQL sublanguages: structure, queries, row changes, permissions, transactions.; Data Management - Foundations
DDoS: Distributed denial of service: flooding a system from many machines so users cannot reach it.; Introduction to IT Network and Security - Foundations Networks+2
Decentralized IT: Each business unit or location runs its own IT.; Introduction to IT
Decision rights: Who has authority to make a given IT decision.; Technology Governance
Decision table: Conditions and the action for each, written before coding.; Python for IT Automation
Dedicated Host: A physical server dedicated to one customer.; Cloud Foundations
DEFAULT: Keyword that uses a column's default value.; Data Management - Applications
Default gateway: The local router a device sends traffic to when it leaves the local network.; Introduction to IT Network and Security - Foundations Networks+1
Default route: The 0.0.0.0/0 route used when no more specific route matches; the gateway of last resort.; Networks
Defense in depth: Layering several controls so one failure does not expose everything.; Introduction to IT Network and Security - Applications
Definition of Done: The formal quality description an Increment must meet to be released.; Agile Methodology
Degaussing: Erasing magnetic media with a powerful magnetic field.; IT Applications
Degraded array: A RAID array running with a failed drive and reduced or no protection.; IT Foundations
Delegation poker: Management 3.0 exercise where leader and team agree a delegation level per decision area.; Agile Processes and Culture in Technology
DELETE: DML statement that removes rows.; Data Management - Foundations
DELETE FROM ... WHERE: Removes the rows that match.; Data Management - Applications
Delimiter: Characters or tags that mark where input data begins and ends.; Practical Applications of Prompt Linux Foundations
Denormalization: Deliberately adding redundancy back for performance.; Data Management - Foundations
Dependency: A task that cannot start until another task is finished.; Business Productivity Software Linux Foundations
Deployer: Under the EU AI Act, the party using an AI system under its authority in a professional capacity.; Data and AI Strategy
Depreciation: Allocation of a tangible asset's cost over its useful life.; Financial Planning for IT Professionals
Deprovisioning: Removing access when a person leaves or no longer needs it.; Network and Security - Applications
Derived table: A subquery in FROM, treated as a temporary table; needs an alias.; Data Management - Applications
Descriptive link text: Link wording that says where the link goes.; Business Productivity Software
Design factor: A trait of the enterprise, such as size or risk profile, used to tailor COBIT.; Technology Governance
Design thinking: Human-centered approach: empathize, define, ideate, prototype, test.; Problem Solving for Technology Business Problems
Determinant: The column or columns on the left side of a functional dependency.; Data Management - Foundations
Developer mode: Hidden settings for app developers, such as USB debugging, that weaken security if left on.; IT Applications
Device driver: Software that lets the operating system control a piece of hardware.; Introduction to IT
Device file: A file in /dev that represents a piece of hardware or a pseudo-device; Linux Foundations
device_type: Netmiko key selecting the vendor driver and transport.; Python for IT Automation
DevOps and CI/CD: Development and operations working together, using automation to integrate, test and deliver code continuously.; Introduction to IT
DFS: Dynamic frequency selection: 5 GHz access points must move off channels where radar is detected.; IT Foundations
DHCP: Assigns IP addresses to devices automatically.; Introduction to IT Linux Foundations
DHCP exclusion: An address inside the scope that DHCP will not hand out.; IT Foundations
DHCP reservation: A fixed address handed to one MAC address by DHCP.; IT Foundations Networks
DHCP scope: The range of addresses a DHCP server hands out for one subnet.; Networks
DHCPv6: A DHCP service for IPv6; Linux Foundations
Dictionary: Mutable mapping of unique keys to values: {key: value}.; Foundations of Programming (Python)
Dictionary attack: A password attack that tries common words and leaked passwords first.; Introduction to IT
DictReader: Reads each CSV row as a dict keyed by the header row.; Python for IT Automation
Differential backup: Backs up everything that changed since the last full backup.; Introduction to IT IT Applications Network and Security - Applications
Digital signature: A hash encrypted with the sender's private key, proving integrity and origin; Network and Security - Foundations Network and Security - Applications
Digital sovereignty: An organization's or country's control over its own data and technology; Linux Foundations
Digital transformation: Using technology to change how an organization operates and delivers value.; Introduction to IT Digital Transformation in the Enterprise
Digitizer: The touch layer that converts touches into input.; IT Foundations
DIKW: Data, information, knowledge, wisdom: the levels by which raw facts become sound decisions.; Introduction to IT
DIMM: Dual in-line memory module: the desktop and server RAM form factor.; IT Foundations
Direct conversion: Switching from the old system to the new one at a single point in time.; Introduction to IT
Directive control: A control that tells people what to do, such as a policy or an instruction sign.; Network and Security - Applications
Directory traversal: Using ../ in a request to reach files outside the intended folder.; Network and Security - Applications
Disaster recovery plan (DRP): How an organization recovers its information systems after a major failure or loss of facilities.; Introduction to IT
DISTINCT: Removes duplicate rows from the result.; Data Management - Foundations Data Management - Applications
Distribution: A complete operating system built around the Linux kernel; Linux Foundations
Distribution (distro): A packaged version of Linux, such as Ubuntu, Fedora, or Red Hat Enterprise Linux.; IT Applications
Divide and conquer: Starting troubleshooting in the middle of the OSI model and moving up or down based on the result.; Networks
DLP: Data loss prevention: finds and controls sensitive data leaving where it should stay.; Network and Security - Applications
DMAIC: Six Sigma's Define, Measure, Analyze, Improve, Control cycle.; Problem Solving for Technology Business Problems
DMARC: A DNS TXT policy telling receivers how to treat mail that fails SPF or DKIM.; IT Foundations
DMZ: A separate network segment for public-facing servers; Network and Security - Foundations
DNS: Translates names into IP addresses.; Introduction to IT
DNS cache: Recent name lookups a computer remembers to answer faster; Network and Security - Foundations
DNS cache poisoning: Planting false records in a DNS resolver to redirect users.; Network and Security - Applications
DNSSEC: Signatures on DNS records that let resolvers verify answers are genuine.; Networks
Do Not Disturb (Focus): A setting that silences notifications so they do not appear on screen.; Business Productivity Software
Docking station: A desk unit that connects a laptop to power, monitors, network and peripherals through one connection.; IT Foundations
Domain: A centrally managed network where accounts and policies are stored in Active Directory.; IT Applications
DORA metrics: Software delivery performance measures from the DevOps Research and Assessment program.; Agile Processes and Culture in Technology
Dot voting: Members place a fixed number of votes to prioritize options quickly.; Agile Methodology
DPIA: Data protection impact assessment, required by GDPR for high-risk processing.; Risk Management and Information Technology Data and AI Strategy
Drift: Difference between declared code and live resources.; Cloud Applications
Driver: Code that lets the kernel control a device; Linux Foundations
DROP TABLE: DDL statement that removes a table and all of its rows.; Data Management - Foundations Data Management - Applications
DRP: The plan for restoring IT systems and data after a disruption; Network and Security - Foundations
Dual boot: Two operating systems on one computer, chosen at startup; Linux Foundations
Dual stack: Running IPv4 and IPv6 at the same time on the same devices.; Networks
Dual-channel: Two memory channels used together for more bandwidth.; IT Foundations
Due diligence: Checking a vendor's security, finances and practices before signing.; Network and Security - Applications
Duplex: Printing on both sides of the paper.; IT Foundations

E

EAP-TLS: An 802.1X method that uses certificates on both client and server.; Network and Security - Applications
East-west traffic: Traffic between servers inside a data center, as opposed to north-south traffic entering or leaving it.; Networks
EBITDA: Earnings before interest, taxes, depreciation and amortization; a proxy for operating cash profit.; Financial Planning for IT Professionals
ECC: Error-correcting code memory that fixes single-bit errors.; IT Foundations
Economies of scale: Lower unit prices that come from operating at very large volume.; Cloud Foundations
Edge case: Input at a boundary: empty, zero, one item, maximum.; Foundations of Programming (Python)
Edge computing: Processing data near its source for speed and lower bandwidth use.; Introduction to IT Digital Transformation in the Enterprise
Edge location: A site that caches content and serves DNS close to users.; Cloud Foundations
EDM: Evaluate, Direct, Monitor: the governance cycle in COBIT and ISO/IEC 38500.; Technology Governance
EDR: Endpoint detection and response: tools that watch devices for attacks and help respond.; Introduction to IT IT Applications Network and Security - Applications
Effective challenge: SR 11-7 term: critical review of a model by qualified, independent people with authority to require changes.; Data and AI Strategy
EFS: Encrypting File System: per-file encryption tied to a user's certificate.; IT Applications
Egress: Data leaving a cloud provider's network, usually billed.; IT Foundations
Egress fee: A cloud provider's charge for data transferred out of its network.; Financial Planning for IT Professionals
Eisenhower matrix: A grid that sorts tasks by urgency and importance into do, schedule, delegate and drop.; Business Productivity Software
Elasticity: Automatically adding and removing resources to match demand.; Cloud Foundations
Elevated prompt: A command window started with Run as administrator, needed for commands that change the system.; IT Applications
Email rule: An instruction that automatically sorts, flags or forwards messages.; Business Productivity Software
EmailMessage: Standard class for building messages with headers and body.; Python for IT Automation
Embedded and linked charts: Pasted charts that hold their own copy of the data, or stay connected to the workbook.; Fundamentals of Spreadsheets and Data Presentations
Embedded system: A computer built into a device to do one job, such as a router; Linux Foundations
Emerging technology: A technology that is new or recently and significantly updated, with adoption still growing.; Digital Transformation in the Enterprise
EMI: Electromagnetic interference from electrical equipment that disrupts copper signals; Network and Security - Foundations
Empiricism: Making decisions from observation and experience, through transparency, inspection and adaptation.; Agile Methodology Agile Processes and Culture in Technology
Encapsulating Security Payload (ESP): The IPsec protocol that encrypts and authenticates the protected data.; Networks
Encapsulation: Each layer wrapping the data from the layer above with its own header on the way down; Network and Security - Foundations Networks
Encryption at rest: Encrypting stored data.; Cloud Foundations
Encryption in transit: Encrypting data as it moves across a network, usually with TLS.; Cloud Foundations
End of life: The date a release stops receiving security updates; Linux Foundations
End of life (EOL): The date after which a vendor stops supporting a product, including security fixes.; Introduction to IT
End-of-life (EOL): The date after which a vendor no longer provides updates or support for a product.; IT Applications
End-of-support (EOS): The date after which a vendor stops releasing fixes and providing help for a product.; Networks
Endpoint: A device people use directly, such as a laptop or phone.; Introduction to IT Python for IT Automation
Entity: A thing the business tracks; becomes a table.; Data Management - Foundations
Entity integrity: Primary key values are unique and never NULL.; Data Management - Foundations
Environment variable: A variable passed on to programs started from the shell; Linux Foundations
Ephemeral port: A temporary high-numbered source port a client chooses for a single connection.; Networks
ePHI: Health information in electronic form, protected by HIPAA; Network and Security - Foundations
Epic: A large body of work split into smaller stories.; Agile Methodology
Equivalent annual cost: A cost's NPV spread into an equal yearly amount, to compare different lifetimes.; Financial Planning for IT Professionals
ER diagram: A drawing of entities, their attributes and the relationships between them.; Data Management - Foundations
ERE: Extended regular expressions, used by grep -E; Linux Foundations
ERP: Enterprise resource planning: integrated software that runs core operations from one shared database.; Introduction to IT
Err-disabled: A port the switch shut down itself after detecting a violation.; Networks
Error 1451: A parent row cannot be deleted or changed because child rows refer to it.; Data Management - Applications
eSATA: External SATA connection for external drives.; IT Foundations
Escalate: Hand a problem to a higher support tier or a specialist when it is beyond your scope.; IT Foundations Networks
ESD: Electrostatic discharge: static electricity that can damage components without any visible sign.; IT Foundations IT Applications
eSIM: An embedded, reprogrammable SIM built into the device and activated by the carrier.; IT Foundations
ESP: Encapsulating Security Payload: the IPsec protocol that encrypts traffic.; Network and Security - Applications
et al.: "And others": used in APA 7 in-text citations for three or more authors.; Technical Communication
ETL: Extract, transform, load: moving data from sources into a form ready for analysis.; Cloud Foundations
EULA: End-user license agreement: the terms that grant the right to use software, not own it.; Introduction to IT IT Applications
Evil twin: A fake access point that copies a real network's name.; IT Applications Networks Network and Security - Applications
Excel table: A named, self-expanding list with headers, filters and structured references.; Fundamentals of Spreadsheets and Data Presentations
Exception: A documented, approved and time-limited decision not to fix a finding yet.; Network and Security - Applications Foundations of Programming (Python)
Execution policy: PowerShell's setting that controls whether and which script files may run.; IT Applications
Executive summary: Standalone short version of a report for decision-makers.; Technical Communication
EXISTS: True when the subquery returns at least one row.; Data Management - Applications
Exit code: Number a program returns; 0 means success.; Python for IT Automation
Exit status: A number from 0 to 255 a command returns; 0 means success; Linux Foundations
Exit strategy: A documented, tested plan to move a workload off a provider.; Cloud Strategy
Expected monetary value (EMV): Probability multiplied by impact, summed across risks.; Project Management
Exploit: The method or code that takes advantage of a vulnerability; Network and Security - Foundations
export: The builtin that turns a shell variable into an environment variable; Linux Foundations
Exposure factor: The share of an asset's value lost in one occurrence.; Network and Security - Applications
Expression: Code that produces a value.; Foundations of Programming (Python)

F

f-string: f"..." with {expressions} filled in.; Foundations of Programming (Python)Python for IT Automation
Facilitation: Guiding a meeting's process so the group reaches its purpose; not deciding the content.; Agile Methodology
Fail-closed: A failed device blocks traffic, favoring security.; Network and Security - Applications
Fail-open: A failed device lets traffic through, favoring availability.; Network and Security - Applications
FAIR: Factor Analysis of Information Risk: quantitative model of loss event frequency and magnitude.; Risk Management and Information Technology Cybersecurity Strategy
False negative: A real vulnerability or attack that a tool missed.; Network and Security - Applications
Fault tree analysis: Top-down logic diagram of the conditions that lead to a failure.; Problem Solving for Technology Business Problems
Federated model: Central IT runs shared services and standards; units handle local needs.; Technology Governance
Federation: Letting users sign in with an existing identity provider instead of new AWS credentials.; Cloud Foundations
Few-shot prompting: Including a few worked examples so the model follows the pattern.; Practical Applications of Prompt
Field: One column of a line, separated by a delimiter; Linux Foundations
File storage: A shared network file system; Amazon EFS and Amazon FSx.; Cloud Foundations
Fileless malware: Malware that runs in memory through legitimate tools and leaves little on disk.; IT Applications Network and Security - Applications
Filesystem: The structure an OS uses to store, name, and find files on a drive.; IT Applications
FileVault: macOS full-disk encryption.; IT Applications
Fill handle: The square at a selection's corner that copies values or continues a series.; Fundamentals of Spreadsheets and Data Presentations
Filter: Hides rows that do not meet the chosen conditions.; Fundamentals of Spreadsheets and Data Presentations
find: The command that searches the tree for files by name and other tests; Linux Foundations
FinOps: Cloud financial management shared by finance, engineering and business teams.; Technology Governance Financial Planning for IT Professionals Cloud Strategy+1
Firewall: Allows or blocks traffic based on rules.; Introduction to IT
Firmware: Low-level software stored on a hardware chip that starts and controls the device.; Introduction to IT
First Hop Redundancy Protocol (FHRP): A protocol that lets routers share a virtual gateway address so a router failure does not cut hosts off.; Networks
Fishbone diagram: Ishikawa cause-and-effect diagram grouping potential causes by category.; Problem Solving for Technology Business Problems
Flash Fill: Fills a column by copying a pattern from typed examples.; Fundamentals of Spreadsheets and Data Presentations
Flipped interaction: A pattern where the model asks the user questions instead of answering right away.; Practical Applications of Prompt
Flow data: Summary records of network conversations, such as NetFlow, without the payload.; Networks
Flow efficiency: Active work time as a share of total lead time.; Agile Processes and Culture in Technology
Folder redirection: Storing folders such as Documents on a network share instead of in the local profile.; IT Applications
Folder structure: The agreed layout of folders in a shared location.; Business Productivity Software
for loop: Repeats commands once for each item in a list; Linux Foundations
Forecast: AWS's projection of spending for the rest of the period, based on usage so far.; Cloud Foundations
Foreign key: A column that refers to another table's primary key.; Introduction to IT Data Management - Foundations
Formula: A calculation that starts with = and updates when its inputs change.; Fundamentals of Spreadsheets and Data Presentations
Forward secrecy: Past sessions stay safe even if a long-term private key is stolen later.; Network and Security - Applications
Four-fifths rule: Adverse impact indicator: a group's selection rate below 80% of the highest group's rate.; Data and AI Strategy
Framework: A structured set of practices for running a security program; Network and Security - Foundations
Free software: Software that grants the FSF's four freedoms; Linux Foundations
Free/busy: The availability other people see when they schedule with you.; Business Productivity Software
Freeware: Software that is free to use but whose code stays closed.; Introduction to IT
Freeze Panes: Keeps chosen rows or columns visible while scrolling.; Fundamentals of Spreadsheets and Data Presentations
Function: A named, built-in calculation such as SUM or AVERAGE.; Fundamentals of Spreadsheets and Data Presentations Foundations of Programming (Python)
Functional dependency: A → B: each value of A is paired with exactly one value of B.; Data Management - Foundations
Functional requirement: What a system must do, such as showing a customer's balance.; Introduction to IT
Fuser: The heated rollers that melt toner onto the page.; IT Foundations

G

Gap analysis: A comparison of the current state with a framework's requirements.; Network and Security - Applications Information Technology Management and Leadership Leading a Technology Transformation
GDPR: EU law on personal data of people in the EU, applied since May 25, 2018.; Introduction to IT
Generation 2 VM: A Hyper-V VM with UEFI firmware, Secure Boot and virtual TPM support.; IT Foundations
Generative AI: AI that produces new content, such as text or images, from prompts.; Introduction to IT Practical Applications of Prompt
get(): Lookup that returns None or a default instead of raising.; Foundations of Programming (Python)
Getter: NAPALM method returning structured device data.; Python for IT Automation
GFS: Grandfather-father-son: a rotation that keeps daily, weekly, and monthly backup sets.; IT Applications
Ghosting: A faint repeated image on a page, also called a double or echo image.; IT Foundations
Giant: A frame larger than the allowed maximum, often from an MTU mismatch.; Networks
Given/When/Then: A format for acceptance criteria: precondition, action, expected result.; Agile Methodology
Glob: A wildcard pattern the shell expands into matching file names; Linux Foundations
gMSA: A Windows service account whose password the system manages and rotates automatically.; Network and Security - Applications
Goals cascade: COBIT method linking stakeholder needs to enterprise goals, alignment goals and objectives.; Technology Governance
Golden configuration: The approved standard configuration used to build devices and check them for drift.; Networks
Govern function: CSF 2.0 function covering cybersecurity risk strategy, roles, policy, oversight and supply chain risk.; Cybersecurity Strategy
Governance: Evaluating options, directing priorities and monitoring results on behalf of stakeholders.; Technology Governance
GPL: An open-source license that sets conditions on how changed code may be shared.; Introduction to IT
GPS: Global positioning system: location from satellite signals.; IT Foundations
GPT (GUID Partition Table): Modern partition style used with UEFI; supports very large disks and up to 128 partitions in Windows.; IT Applications
Grounding: Restricting an answer to supplied source material to reduce fabrication.; Practical Applications of Prompt
GROUP BY: Forms groups of rows that share values, one summary row per group.; Data Management - Foundations Data Management - Applications
Guard clause: Early return or continue that removes a case up front.; Python for IT Automation
Guardrail: An automated preventive, detective or corrective control that enforces a governance policy.; Cloud Strategy
Guideline: Recommended practice that is not mandatory.; Network and Security - Applications
Guiding coalition: Kotter's group with enough power and credibility to lead the change.; Agile Processes and Culture in Technology Leading a Technology Transformation

H

Hallucination: An AI answer that sounds confident but is false.; IT Applications
Hanging indent: First line flush left, following lines indented 0.5 inch.; Technical Communication
Hard link: Another directory entry for the same file data; Linux Foundations
Hash: A fixed-length fingerprint of a file; any change to the file changes the hash.; IT Applications Network and Security - Foundations Network and Security - Applications
Hash table: A table whose rows are placed in buckets by a hash function on a key.; Data Management - Foundations
HAVING: Filters groups after aggregation; WHERE filters rows before it.; Data Management - Foundations Data Management - Applications
Heading style: A built-in paragraph style that marks a heading and its level.; Business Productivity Software
Heap table: A table with no row order.; Data Management - Foundations
Hibernate: A power state that saves the session to disk and turns the computer off.; IT Applications
Hidden file: A file whose name starts with a dot; Linux Foundations
High availability: Designing a system so it keeps working when a component fails.; Cloud Foundations
HIPAA: U.S. law on how health plans, providers and their associates use and disclose protected health information.; Introduction to IT
Histogram: Bars showing how many values fall in each range.; Technical Communication
Hit ratio (selectivity): The share of a table's rows that a query returns.; Data Management - Foundations
Home directory: A user's own directory, written ~; Linux Foundations
Honeypot: A decoy system that attracts attackers so their activity can be detected and studied.; Networks
Hop: One router along the path between two hosts; Network and Security - Foundations
Hot site: An alternate site fully equipped with near-current data, ready within hours.; Introduction to IT Networks Network and Security - Applications
Hot, warm and cold sites: Recovery sites ready in minutes, hours or days; Network and Security - Foundations
Hotspot: A phone or small device acting as a Wi-Fi access point that shares its cellular data.; IT Foundations
HSM: A tamper-resistant device or service that generates and stores keys at scale.; Network and Security - Applications
Hurdle rate: Minimum acceptable return on an investment.; Financial Planning for IT Professionals
Hybrid (federated) IT: Central standards and shared services, plus local IT staff in business units.; Introduction to IT
Hybrid cloud: Two or more cloud types, such as private and public, used together.; Introduction to IT Cloud Strategy
Hype Cycle: Gartner's model of how expectations for a new technology rise, fall and settle.; Introduction to IT
Hypercare: A period of heightened support right after go-live.; Leading a Technology Transformation
Hypervisor: Software that lets one physical server run many virtual machines.; Introduction to IT IT Foundations Network and Security - Foundations+1

I

IaaS: Infrastructure as a service: virtual servers, storage and networks; the customer manages the OS and up.; Introduction to IT IT Foundations Cloud Foundations
IAM Identity Center: AWS's service for workforce single sign-on to multiple AWS accounts and applications.; Cloud Foundations
IAM role: An identity assumed temporarily that provides short-term credentials.; Cloud Foundations
ICMP: The protocol for network error and test messages, used by ping; Network and Security - Foundations
ICMP echo: The request and reply messages that ping uses; Network and Security - Foundations
IDE: Integrated development environment: editor, runner and debugger in one.; Foundations of Programming (Python)
Idempotent: Same result no matter how many times it runs.; Python for IT Automation Cloud Applications
Identifier: The name of a database object such as a table or column.; Data Management - Foundations
Identity proofing: Verifying a person's identity before issuing credentials.; Network and Security - Applications
Identity synchronization: Copying user accounts from an on-premises directory to a cloud directory so users have one sign-in.; IT Applications
IDF: Intermediate distribution frame: a wiring closet that serves one floor or area and links back to the MDF.; Networks
IDS and IPS: Systems that detect intrusions; an IPS can also block them; Network and Security - Foundations
IF: Returns one value when a test is true and another when it is false.; Fundamentals of Spreadsheets and Data Presentations
IFERROR: Returns a chosen value instead of an error.; Fundamentals of Spreadsheets and Data Presentations
IG1: CIS Controls Implementation Group 1: the essential cyber hygiene safeguards every organization should implement.; Cybersecurity Strategy
Immutable backup: A backup that cannot be changed or deleted during its retention period.; Network and Security - Applications
Impact analysis: An assessment of what a change could affect, including its security effects.; Network and Security - Applications
Impediment: Anything blocking the team's progress.; Agile Methodology
Implementation Groups: CIS tiers IG1–IG3 that prioritize safeguards by organization size, risk and resources.; Cybersecurity Strategy
Implicit commit: An automatic commit caused by statements such as DDL.; Data Management - Applications
Implicit deny: Blocking everything that is not explicitly allowed; Network and Security - Foundations Networks Network and Security - Applications
In-place upgrade: Installing a newer OS version over the current one while keeping files, settings, and apps.; IT Applications
Incident: An event that harms or threatens confidentiality, integrity or availability, or breaks policy.; Network and Security - Applications
Incident commander: The single decision-maker running the response.; Risk Management and Information Technology
Incident management: Restoring normal service as quickly as possible after something breaks.; Introduction to IT
Incident response plan: A plan, made in advance, of who does what when an attack happens.; Introduction to IT
Increment: A usable piece of the product delivered at the end of an iteration.; Agile Methodology
Incremental backup: Backs up only what changed since the last backup of any kind.; Introduction to IT IT Applications Network and Security - Applications
Index: A sorted structure of column values with pointers to rows, used to find rows quickly.; Data Management - Foundations Foundations of Programming (Python)
INDEX and MATCH: A pair of functions that look up a value in any direction.; Fundamentals of Spreadsheets and Data Presentations
Indicator of compromise: Evidence that a system has been attacked or breached.; Network and Security - Applications
Infinite loop: A while loop whose condition never becomes False.; Foundations of Programming (Python)
Information assurance: Confidence that information keeps its confidentiality, integrity, availability, authenticity and non-repudiation.; Risk Management and Information Technology
Information radiator: A large, visible display of team status that anyone can read.; Agile Methodology
Information system: Hardware, software, data, networks, people and procedures that turn data into information for decisions.; Introduction to IT
Information technology (IT): The use of computers, networks, software and data to support an organization's work.; Introduction to IT
Infrastructure: The hardware, software, network, data, cloud services, people and processes that deliver IT services.; Information Technology Management and Leadership
Infrastructure as code: Defining infrastructure in template files that are deployed automatically.; Network and Security - Applications
Inherent risk: Exposure before controls are applied.; Risk Management and Information Technology
Inheritance: Files and subfolders receiving the permissions of their parent folder.; IT Applications
Inline: Placed in the traffic path, able to block.; Network and Security - Applications
INNER JOIN: Returns only rows that match in both tables.; Data Management - Applications
Inode: The record that holds a file's data location and attributes; Linux Foundations
INSERT: DML statement that adds new rows.; Data Management - Foundations
INSERT ... SELECT: Adds the rows returned by a query.; Data Management - Applications
INSERT INTO ... VALUES: Adds one or more rows with the values given.; Data Management - Applications
Insider threat: An employee or contractor who misuses access, on purpose or by accident.; Introduction to IT Network and Security - Applications
Instance: A virtual server in Amazon EC2.; Cloud Foundations
Instance store: Temporary block storage on the host; data is lost when the instance stops or terminates.; Cloud Foundations
Interpreter: Reads and runs code one statement at a time.; Introduction to IT IT Applications Foundations of Programming (Python)
Inverter: A board that powered fluorescent backlights in older LCDs.; IT Foundations
IOPS: Input/output operations per second: a measure of storage performance.; IT Foundations
IoT: Internet of Things: everyday objects with sensors and network connections.; Introduction to IT
IP address: A number that identifies a device on a network so data can reach it.; Introduction to IT
IP helper: A router setting that relays DHCP broadcasts to a server on another subnet.; Networks
ipaddress: Standard module that validates addresses and networks.; Python for IT Automation
IPAM: IP address management: tracking which addresses and subnets are used, and by what.; Networks
IRR: Internal rate of return: the discount rate at which NPV equals zero.; Financial Planning for IT Professionals
Is / is not analysis: Kepner-Tregoe contrast of where a problem occurs and where it could but does not.; Problem Solving for Technology Business Problems
ISAC: Information sharing and analysis center: an industry group that shares threat information.; Network and Security - Applications
ISMS: An information security management system, as defined by ISO/IEC 27001; Network and Security - Foundations Technology Governance Risk Management and Information Technology
ISO 31000: International guideline for managing any type of risk: principles, framework, process.; Risk Management and Information Technology
ISO file: A disk image used to install an operating system in a VM.; IT Foundations
ISO image: A file holding a complete disc image, used as installation media; Linux Foundations
Isolation level: How much a transaction can see of other transactions' uncommitted work.; Data Management - Applications
IT governance: The structures, policies and frameworks that keep IT decisions accountable to the business.; Introduction to IT
ITAM: IT asset management: tracking hardware, software and licenses through their lifecycle.; Technology Governance
Item 1.05 (Form 8-K): SEC requirement to disclose a material cybersecurity incident within four business days of the materiality determination.; Cybersecurity Strategy
Item 106 (Regulation S-K): Annual 10-K disclosure of cybersecurity risk management, strategy and governance.; Cybersecurity Strategy
Iteration: Repeated cycles of prompting, evaluating and refining.; Practical Applications of Prompt Foundations of Programming (Python)
ITIL: The best-known ITSM framework; ITIL 4 is widely certified, and ITIL (Version 5) arrived in 2026.; Introduction to IT
ITSM: IT service management: running IT as a set of services with owners, quality targets and support processes.; Introduction to IT

J

J-curve: Temporary performance dip after a change before improvement.; Leading a Technology Transformation
Jailbreak or root: Removing the OS restrictions on a phone to gain full control, which also removes security protections.; IT Applications
Jitter: Variation in latency from packet to packet.; IT Foundations Networks
Join: Combines rows from two tables based on a condition.; Data Management - Foundations
Join condition: The rule that matches rows, usually foreign key = primary key.; Data Management - Applications
Journal: systemd's log store, read with journalctl; Linux Foundations
Journaling: The filesystem logs changes before making them, so it can recover cleanly after a crash or power loss.; IT Applications
JSON: Text format for nested data; objects map to dicts, arrays to lists.; Python for IT Automation
Jumbo frame: An Ethernet frame with a payload larger than 1500 bytes, commonly up to about 9000.; Networks
Jump box: A hardened host administrators connect through to reach managed devices.; Networks
Jump server: A hardened host administrators use to reach secure systems.; Network and Security - Applications
Just culture: Errors are reported without blame so the organization learns; willful violations are still handled.; Cybersecurity Strategy
Just-in-time access: Temporary, approved access that expires automatically.; Network and Security - Applications

K

Kaizen: Continuous, incremental improvement.; Agile Methodology
Kanban board: A board whose columns show stages of work and whose cards move across as work progresses.; Business Productivity Software
Kerberos: The ticket-based authentication protocol used in Windows domains.; IT Applications
Kernel: The core of the operating system that controls hardware and processes; Linux Foundations Foundations of Programming (Python)
Kernel module: A driver or feature loaded into the kernel while it runs; Linux Foundations
Kernel ring buffer: The kernel's recent messages, read with dmesg; Linux Foundations
Key escrow: Keeping a protected copy of keys with a trusted party so data can be recovered.; Network and Security - Applications
Key exchange: A method such as Diffie-Hellman that lets two parties agree on a secret key over an open network.; Network and Security - Applications
Key stretching: Making each password guess slow on purpose, with algorithms such as bcrypt or PBKDF2.; Network and Security - Applications
Key-person risk: Dependence on one person whose loss stops a function.; Technology Governance
KeyError: Raised by d[key] when the key is missing.; Foundations of Programming (Python)
Keystone: Projector correction for a trapezoid-shaped image.; IT Foundations
Kirkpatrick model: Four levels of training evaluation: reaction, learning, behavior, results.; Leading a Technology Transformation
Knock-out criterion: A mandatory requirement; failing it removes the option regardless of score.; Cloud Strategy
Known error: ITIL: a problem with a documented root cause or workaround.; Problem Solving for Technology Business Problems
known_hosts: The client file of server keys it has seen before; Linux Foundations
KPI: Key performance indicator: a measure that shows progress toward a goal.; Information Technology Management and Leadership
KRI: Key risk indicator: a metric that warns of increasing risk.; Technology Governance Risk Management and Information Technology Cybersecurity Strategy

L

Label: A colored tag that marks tasks sharing a trait, such as 'blocked' or 'hardware.'; Business Productivity Software
Lakehouse: Lake storage plus open table formats giving ACID transactions, schema enforcement and time travel for BI and ML.; Data and AI Strategy
LAN and WAN: A local area network covers one site; a wide area network links sites across distance.; Introduction to IT
Landing zone: A pre-configured, multi-account cloud environment with identity, network, logging and guardrails, ready for workloads.; Cloud Strategy Leading a Technology Transformation
Landmark: Region a screen reader can jump to: banner, navigation, main, contentinfo.; Web Design Fundamentals
LAST_INSERT_ID(): Returns the AUTO_INCREMENT value most recently generated in the session.; Data Management - Applications
Latency: How long data takes to arrive, measured in milliseconds.; Introduction to IT IT Foundations Networks
Lateral reading: Checking a claim by leaving the source and reading what other reliable sources say.; Practical Applications of Prompt
Leadership agility: Capacity to lead effectively under rapid change and complexity; Joiner and Josephs' five levels.; Agile Processes and Culture in Technology
Least privilege: Giving each user only the access their job requires.; Introduction to IT Business Productivity Software IT Applications+4
LEFT JOIN: Returns every row of the left table plus matching rows from the right; NULLs where none match.; Data Management - Applications
Leftmost-prefix rule: A composite index helps only queries that use its first column or columns.; Data Management - Foundations
Legacy system: An older system still in use that may be hard to maintain or change.; Introduction to IT
Legal hold: An instruction to preserve data relevant to a legal matter.; Network and Security - Applications
LeSS: Large-Scale Scrum: many teams, one Product Owner and one Product Backlog.; Agile Processes and Culture in Technology
LGA: Land grid array: a CPU socket with the pins in the socket.; IT Foundations
Lifecycle rule: An S3 rule that moves or deletes objects after a set time.; Cloud Foundations
Lightweight AP: An access point managed by a wireless LAN controller rather than configured on its own.; Networks
LIKE: Pattern match on text using % (any characters) and _ (one character).; Data Management - Foundations
LIMIT ... OFFSET: Returns a set number of rows after skipping some.; Data Management - Applications
Line total: Quantity times sale price for one order line; summed for order or customer totals.; Data Management - Applications
Lineage: Record of a data element's origin and every transformation to its current use.; Data and AI Strategy
Liquid contact indicator: A sticker inside a device that changes color when it gets wet.; IT Foundations
List: Ordered, mutable sequence; duplicates allowed: [ ].; Foundations of Programming (Python)
List comprehension: [expression for item in iterable if condition].; Foundations of Programming (Python)
Literal: A fixed value written in a statement, such as 'Open' or 42.; Data Management - Foundations
Little's Law: Average cycle time = average WIP ÷ average throughput, for a stable system.; Agile Processes and Culture in Technology
Live session: Running Linux from the installation USB without installing it; Linux Foundations
Living off the land: Attacking with tools already present on the system, such as PowerShell.; Network and Security - Applications
LLDP: Link Layer Discovery Protocol: an open standard for devices to announce themselves to directly connected neighbors.; Networks
Loaded labor rate: Salary plus benefits and overhead per hour.; Financial Planning for IT Professionals
Log level: Severity that filters which messages are recorded.; Python for IT Automation
Logic bomb: Malicious code that triggers when a condition is met.; Network and Security - Applications
Logic error: Wrong result with no error message.; Foundations of Programming (Python)
Logical design: Turning the model into tables, columns and keys.; Data Management - Foundations
Logical diagram: A diagram of how traffic flows: subnets, VLANs, routing, and security zones.; Networks
Loop: A block of code that repeats for each item or until a condition is met.; IT Applications
Loopback plug: A plug that sends a port's output back to its input for testing.; IT Foundations
LTS: Long-term support: a release maintained with fixes for several years; Linux Foundations

M

M.2: A small card form factor for SSDs and wireless cards; an M.2 SSD can use SATA or NVMe.; IT Foundations
MAC address: A 48-bit hardware address used to deliver frames on the local network; Network and Security - Foundations
MAC address table: The switch's list of which MAC addresses were seen on which ports and VLANs.; Networks
MAC flooding: Overfilling a switch's MAC table so it floods frames out every port.; Networks
Machine code: Binary instructions a processor executes directly.; Introduction to IT
Machine learning: A branch of AI in which systems learn patterns from data rather than following fixed rules.; Introduction to IT Cloud Foundations
Main guard: The if-name-equals-main test that runs code only when the file is executed directly.; Python for IT Automation
Maintenance kit: A laser printer kit with a fuser and rollers, replaced at a set page count.; IT Foundations
Maintenance window: A scheduled time when changes may be made with the least disruption.; IT Applications Network and Security - Applications
Man page: The built-in reference manual for a command or file; Linux Foundations
Managed database service: A cloud offering in which the provider runs patching, backups and failover.; Data Management - Applications
Managed service provider (MSP): An outside company that runs IT services under contract.; Introduction to IT
Managed switch: A switch that can be configured: VLANs, port settings, monitoring.; IT Foundations
Management: Planning, building, running and monitoring activities within the direction governance sets.; Technology Governance
Managerial control: A safeguard that comes from management decisions and documents, such as policy or risk assessment.; Network and Security - Applications
Maturity level: Organization-wide rating, 0 to 5, of process maturity.; Technology Governance
Maturity model: A staged scale for scoring capability, used to set a baseline and target.; Data and AI Strategy
Maximum cardinality: The most instances that can relate: one or many.; Data Management - Foundations
MDF: Main distribution frame: the building's central equipment room.; Networks
MDM: Mobile device management: software that enrolls, configures, secures and wipes mobile devices.; IT Foundations Network and Security - Applications
Memory leak: A program that keeps claiming memory without releasing it, slowing the system over time.; IT Applications
Message queue: A buffer that holds messages until a consumer processes them.; Cloud Foundations
Metadata: Information about a file, such as owner or status, used to sort and filter it.; Business Productivity Software Data Management - Foundations
Metered connection: A connection Windows treats as limited, so it reduces background downloads.; IT Applications
MFA: Multifactor authentication: two or more kinds of proof of identity.; Introduction to IT Network and Security - Foundations Networks
MIB: Management information base: the description of the values an SNMP agent can report.; Networks
Microservices: An application built from small, independent services that talk over APIs.; Network and Security - Applications
Microsoft Defender Offline: A Defender scan that runs outside normal Windows to remove malware that hides while Windows is running.; IT Applications
Migration wave: A group of dependent applications moved together on a scheduled date.; Cloud Strategy
Millimeter wave: High-band 5G: very fast but short range and easily blocked.; IT Foundations
MIMO: Using multiple antennas to send and receive several streams at once; Network and Security - Foundations
Minimum cardinality: The fewest that must relate: zero (optional) or one (required).; Data Management - Foundations
MITRE ATT&CK: A knowledge base of attacker tactics and techniques.; Network and Security - Applications
Mixed reference: A reference with only the column or only the row locked, such as $A1 or A$1.; Fundamentals of Spreadsheets and Data Presentations
MLOps: Practices that automate and govern the ML lifecycle: pipelines, versioning, deployment, monitoring and retraining.; Data and AI Strategy
MMC snap-in: A management tool that runs inside the Microsoft Management Console, such as Device Manager or Event Viewer.; IT Applications
Model card: A short document stating a model's intended use, data, performance by group, limits and owner.; Data and AI Strategy
MODIFY: ALTER TABLE clause that redefines a column but keeps its name.; Data Management - Applications
Modular PSU: A power supply with detachable cables.; IT Foundations
Module: One .py file that can be imported.; Python for IT Automation
Modulo: % gives the remainder.; Foundations of Programming (Python)
Moore's law: Gordon Moore's observation that transistor counts on chips doubled about every two years.; Introduction to IT
MoSCoW: Prioritization into Must, Should, Could and Won't have this time.; Agile Methodology
MSA: Master service agreement: the umbrella terms for an ongoing relationship.; Network and Security - Applications
MTBF: Mean time between failures: the average running time between failures.; Networks Network and Security - Applications
MTD: Maximum tolerable downtime for a business process.; Risk Management and Information Technology
MTTD / MTTR: Mean time to detect / mean time to respond (or recover) to incidents.; Cybersecurity Strategy
MTTR: Mean time to repair: the average time to fix a failed component.; Networks Network and Security - Applications Problem Solving for Technology Business Problems
Muda: Activity that consumes resources without creating customer value.; Agile Methodology
Multi-table join: A query that chains joins so each new table links to one already present.; Data Management - Applications
Multi-table UPDATE: A MySQL UPDATE that joins tables to decide new values.; Data Management - Applications
Multicloud: Using more than one public cloud provider at the same time.; Introduction to IT
Multilayer switch: A switch that can also route traffic between VLANs at Layer 3.; Networks
Multimode fiber: Fiber with a larger core for shorter, cheaper links inside buildings and data centers.; Networks
Multitenancy: Many customers sharing infrastructure while kept separate.; IT Foundations
Mutable: Can change in place.; Foundations of Programming (Python)Python for IT Automation
MVOTs: Multiple versions of the truth: purpose-built views derived from the SSOT for specific uses.; Data and AI Strategy

N

NAC: Network access control: checks identity and device health before granting network access.; Network and Security - Applications
Named range: A name assigned to a cell or range, used in formulas like an absolute reference.; Fundamentals of Spreadsheets and Data Presentations
Naming convention: An agreed pattern for file names, such as date, topic and document type.; Business Productivity Software
NAS and SAN: Network-attached storage shares files over the network; a storage area network gives servers fast block-level storage.; Introduction to IT
NAT: Translating private addresses to a public address at the network edge; Network and Security - Foundations
NAT gateway: A cloud service that lets private resources reach the internet without accepting inbound connections.; Networks
Native resolution: The physical pixel grid of a panel; the setting that looks sharpest.; IT Foundations
Native VLAN: The VLAN that crosses a trunk without a tag; it must match on both ends.; Networks
Natural key: An identifier taken from real-world data.; Data Management - Foundations
Navigation pane: Word's panel that lists the headings so you can jump between sections.; Business Productivity Software
Negative prompt: A list of elements the image model should avoid.; Practical Applications of Prompt
NetFlow: Records of network conversations without their content.; Network and Security - Applications
netstat: A command that lists active connections and listening ports.; Networks
Network access control (NAC): Checking a device's identity and health before letting it onto the network.; Networks
Network ACL: A stateless firewall for a subnet with allow and deny rules.; Cloud Foundations
Network engineer: Designs, builds and maintains the networks that connect devices and sites.; Introduction to IT
Network segmentation: Separating a network into zones so attackers can't move freely to sensitive systems.; Introduction to IT
Network tap: A device that copies link traffic for monitoring.; IT Foundations
Network tap or SPAN port: A way to send a copy of traffic to a monitoring device.; Network and Security - Applications
Neutral zone: Bridges: the in-between period after the old way ends and before the new way is accepted.; Leading a Technology Transformation
Newline: The "\n" at the end of each line read from a file.; Foundations of Programming (Python)
NIST CSF: NIST's framework of six security functions; Network and Security - Foundations
NIST CSF 2.0: A security framework with six functions: Govern, Identify, Protect, Detect, Respond and Recover.; Introduction to IT Network and Security - Applications Technology Governance+1
NIST SP 800-145: The NIST definition of cloud computing: five characteristics, three service models, four deployment models.; Cloud Strategy
NIST SP 800-61r3: NIST's incident response recommendations aligned to CSF 2.0 (April 2025).; Problem Solving for Technology Business Problems
Nmap: A scanner that finds live hosts, open ports, and running services.; Networks
Non-equijoin: A join whose condition uses an operator other than =.; Data Management - Applications
Non-overlapping channels: Channels far enough apart that they do not interfere; 1, 6 and 11 on 2.4 GHz in North America.; IT Foundations
Non-repudiation: Proof that a sender cannot deny having sent a message; Network and Security - Foundations Network and Security - Applications
Non-transitive peering: A peers with B and B with C does not let A reach C.; Cloud Applications
Nonfunctional requirement: How well a system must work, such as its speed or security.; Introduction to IT
Normalization: Organizing tables so each fact is stored once and linked by keys, avoiding conflicting copies.; Introduction to IT Data Management - Foundations Financial Planning for IT Professionals
NoSQL: Databases that store documents, key-value pairs, wide columns or graphs instead of related tables.; Introduction to IT
Notebook, section, page: OneNote's structure: notebooks hold sections, and sections hold pages.; Business Productivity Software
NPV: Net present value: future cash flows discounted to today, minus the investment. Positive means the project adds value at that discount rate.; Digital Transformation in the Enterprise Technology Governance Financial Planning for IT Professionals
NTFS permissions: Permissions stored on files and folders in NTFS; they apply locally and over the network.; IT Applications
NULL: A marker for a value that is unknown or does not apply; not zero and not an empty string.; Data Management - Foundations
Number format: Controls how a value is displayed without changing it.; Fundamentals of Spreadsheets and Data Presentations
NVMe: Non-volatile Memory Express: the fast protocol for SSDs on PCIe.; IT Foundations

O

Object storage: Storage of whole objects with metadata in buckets, reached through an API; Amazon S3.; Cloud Foundations
OBS Studio: Free, open-source software for screen recording and streaming.; Business Productivity Software
OCSP: A protocol for checking one certificate's revocation status in real time.; Network and Security - Applications
Octal mode: Permissions written as three digits, such as 644; Linux Foundations
Off-by-one: A loop that runs one time too many or too few, usually from range bounds.; Foundations of Programming (Python)
OKR: Objectives and key results: a qualitative goal with 3–5 measurable outcome targets.; Leading a Technology Transformation
OLAP: Online analytical processing: large queries that summarize historical data.; Data Management - Applications
OLTP: Online transaction processing: many small, concurrent reads and writes.; Data Management - Applications
On-Demand: Pay-as-you-go pricing with no commitment.; Cloud Foundations
On-path attack: An attacker intercepting traffic between two parties.; IT Applications Network and Security - Foundations Network and Security - Applications
On-premises: Infrastructure owned and run in the organization's own facilities.; Introduction to IT
ONLY_FULL_GROUP_BY: MySQL mode, on by default, that rejects non-aggregated columns missing from GROUP BY.; Data Management - Applications
ONT: Optical network terminal: where the ISP's fiber ends at the customer site.; IT Foundations
Open source: Software whose source code is public and may be used, changed and shared under its license.; Introduction to IT Linux Foundations Data Management - Applications
Operating expense: An ongoing, pay-as-you-go cost, such as a monthly cloud bill.; Introduction to IT
Operating model: How the organization delivers value: processes, structure, locations, information, suppliers and management system.; Leading a Technology Transformation
Operating system: System software that manages hardware, users and resources and runs applications.; Introduction to IT
Operating system (OS): Software that manages hardware, runs applications, and controls access to the computer.; IT Applications
Operational control: A safeguard carried out by people in daily work, such as training or guard patrols.; Network and Security - Applications
OpEx: Operating expense: ongoing spending, such as a monthly cloud bill.; Cloud Foundations Financial Planning for IT Professionals
ORDER BY: Sorts the result; ASC is the default, DESC reverses it.; Data Management - Foundations
Order of volatility: Collecting evidence from the most short-lived sources (RAM) to the most lasting (backups).; IT Applications Network and Security - Applications
Organization: A person or group with its own functions, responsibilities, authorities and relationships to achieve objectives.; Business of IT - Applications
Organizational unit (OU): A container in Active Directory used to organize objects and apply Group Policy.; IT Applications
OSI model: A seven-layer model of networking used to discuss and troubleshoot one layer at a time.; Introduction to IT Network and Security - Foundations Networks
OSINT: Open-source intelligence: information gathered from public sources.; Network and Security - Applications
Out-of-band management: Managing devices over a path separate from the production network.; Networks Network and Security - Applications
Outlier: A value far outside the range of the others.; Fundamentals of Spreadsheets and Data Presentations
Owner, group, others: The three classes that permissions are set for; Linux Foundations

P

PaaS: Platform as a service: a managed platform where the customer deploys its own code.; Introduction to IT IT Foundations Cloud Foundations
Package: An archive holding a program, its files and its dependency list; Linux Foundations
Package manager: A tool such as apt or dnf that installs, updates, and removes software from trusted repositories.; IT Applications Linux Foundations
Packet loss: Data that never arrives and must be resent or is lost.; IT Foundations
Page file: Space on the drive that Windows uses as overflow for RAM (virtual memory).; IT Applications
Pairing: The one-time process that links two Bluetooth devices so they trust each other.; IT Foundations
Panopto: A video platform for recording, hosting and sharing videos, used by WGU for video submissions.; Business Productivity Software
Parallel conversion: Running the old and new systems side by side until the new one is trusted.; Introduction to IT
Parent and child tables: The referenced table and the referencing table.; Data Management - Foundations
Pareto principle: A small share of causes produces a large share of effects (the 80/20 rule).; Problem Solving for Technology Business Problems
Parity: Calculated data that lets RAID 5 and 6 rebuild a failed drive.; IT Foundations
Partial dependency: A non-key column depending on part of a composite key; violates 2NF.; Data Management - Foundations
Partition: A section of a disk treated as a separate unit; Linux Foundations Data Management - Foundations Data Management - Foundations
Passive reconnaissance: Gathering information without touching the target's systems.; Network and Security - Applications
Passkey: A FIDO2 credential stored on a device that replaces a password and resists phishing.; Network and Security - Applications Linux Foundations
Password spraying: Trying one common password against many accounts; Network and Security - Foundations Network and Security - Applications
Paste Values: Pastes results without the formulas behind them.; Fundamentals of Spreadsheets and Data Presentations
Patch: An update that fixes bugs or security flaws.; Introduction to IT
Patch management: Applying software updates in a planned, timely way.; Introduction to IT
Patch panel: A panel where permanent cable runs end, connected to switches with short patch cords.; Networks
PATH: The list of directories the shell searches for programs; Linux Foundations Foundations of Programming (Python)
pathlib: Object-oriented paths; / joins parts on any OS.; Python for IT Automation
Payback period: Time for cumulative net benefits to repay the initial cost.; Digital Transformation in the Enterprise Financial Planning for IT Professionals Data and AI Strategy
PCI DSS: Industry security standard for organizations that store, process or transmit payment card data.; Introduction to IT Network and Security - Foundations
PDCA: Plan, Do, Check, Act: Deming's iterative improvement cycle.; Problem Solving for Technology Business Problems
PDU: A rack power strip, sometimes metered or remotely switchable.; Networks
PDU (protocol data unit): The name for data at a given layer: bits, frame, packet, segment or datagram, data; Network and Security - Foundations
Penetration test: An authorized attempt to exploit weaknesses, to prove real risk; Network and Security - Foundations
Performance measurement baseline: Integrated scope, schedule and cost baselines used to measure performance.; Project Management
Permission: The level of access someone has to a file, such as view, comment or edit.; Business Productivity Software
Permissive license: A license that allows reuse, even in closed products, with attribution; Linux Foundations
Persistent volume: Container storage that survives container restarts and removal.; Cloud Applications
Persona: A role assigned to the model to set its expertise, vocabulary and viewpoint.; Practical Applications of Prompt
Personal access token: Scoped, expiring credential used instead of a password.; Python for IT Automation
Personal data: Under GDPR, any information relating to an identifiable person; Network and Security - Foundations
PESTLE: Political, economic, social, technological, legal and environmental factors that constrain or influence a provider.; Business of IT - Applications
Phased conversion: Moving to the new system one module or stage at a time.; Introduction to IT
Phishing: Fraudulent messages that trick people into revealing information or running malware.; Introduction to IT
Physical design: Choosing indexes, partitions and storage for a specific DBMS.; Data Management - Foundations
PI Planning: SAFe's face-to-face or remote event where an ART plans the next Planning Interval.; Agile Processes and Culture in Technology
Pickup roller: The roller that pulls paper from the tray.; IT Foundations
PID: The process ID number the kernel gives each process; Linux Foundations
PII: Personally identifiable information: data that can identify a specific person.; IT Applications Network and Security - Foundations
Pillar: One of the six areas of the Well-Architected Framework.; Cloud Foundations
Pilot: A small, real-world trial of a technology before a wider rollout.; Introduction to IT Digital Transformation in the Enterprise Problem Solving for Technology Business Problems+1
Pilot conversion: Moving one group or site to the new system first, then everyone else.; Introduction to IT
Pilot purgatory: Many AI proofs of concept, few reaching production because criteria, funding or ownership are missing.; Data and AI Strategy
Pipe: The | operator, which feeds one command's output into the next command; Linux Foundations
PivotChart: A chart linked to a PivotTable.; Fundamentals of Spreadsheets and Data Presentations
PivotTable: An interactive summary of a list, built by dragging fields into areas.; Fundamentals of Spreadsheets and Data Presentations
PKI: The system of certificate authorities, certificates and keys; Network and Security - Foundations Networks
Plain language: Writing the intended reader can find, understand and use the first time.; Technical Communication
Plaintext and ciphertext: Readable data before encryption, and the unreadable result; Network and Security - Foundations
Playbook: Step-by-step response instructions for a specific type of incident.; Network and Security - Applications Risk Management and Information Technology Cybersecurity Strategy
Plenum: Cable rated for air-handling spaces because it burns with less toxic smoke; Network and Security - Foundations
Plenum-rated: Cable with a fire-resistant, low-smoke jacket required in air-handling spaces.; IT Foundations
Plenum-rated cable: Cable with a fire-resistant, low-smoke jacket, required in air-handling spaces.; Networks
Plural attribute: An attribute that can hold several values for one instance.; Data Management - Foundations
PoE budget: The total power a switch can supply to all of its PoE ports.; Networks
PoE injector: A small device that adds power to one Ethernet cable run.; IT Foundations
Policy: Management's high-level statement of what must be done; Network and Security - Foundations Network and Security - Applications
Policy as code: Governance rules written in machine-readable form, version-controlled and deployed automatically.; Cloud Strategy
Policy enforcement point: The Zero Trust component in the traffic path that allows or blocks a connection.; Network and Security - Applications Cybersecurity Strategy
Polling: Checking a state repeatedly at an interval.; Python for IT Automation
Pomodoro technique: Working in 25-minute focused intervals with short breaks.; Business Productivity Software
Port: A number that identifies a specific service on a device, such as 443 for HTTPS.; Introduction to IT IT Foundations Network and Security - Foundations
Port address translation (PAT): NAT that lets many private hosts share one public address by tracking source ports.; Networks
Port flapping: A switch port going up and down repeatedly.; IT Foundations
Port mirroring: Copying traffic from switch ports or VLANs to a monitoring port.; Networks
Port replicator: A simpler desk unit that duplicates the laptop's ports.; IT Foundations
Port security: A switch feature that limits which or how many MAC addresses can use a port.; Networks
POST: Power-on self-test: the firmware's hardware check at startup.; IT Foundations
Post-implementation review: A check after go-live that the expected benefits were realized.; Financial Planning for IT Professionals Leading a Technology Transformation
PostScript: Adobe's device-independent page description language.; IT Foundations
POUR: Perceivable, Operable, Understandable, Robust: the four WCAG principles.; Web Design Fundamentals
Power supply tester: A tool that checks the voltages on PSU connectors.; IT Foundations
Power/interest grid: Stakeholder map by influence and concern, used to pick engagement level.; Technical Communication
Practice: A set of resources for a type of work, e.g. incident management, change enablement.; Technology Governance
Practice area: A group of related practices, e.g. risk and opportunity management.; Technology Governance
Pre-mortem: Assuming the solution failed and listing why, before launch.; Problem Solving for Technology Business Problems
Precedence: Order operators are applied.; Foundations of Programming (Python)
Preinstallation environment: A minimal operating system started from external media, used for setup and offline repair.; IT Applications
Present value (PV): Today's value of a future cash flow at a given discount rate.; Financial Planning for IT Professionals
Presenter View: A view that shows the presenter the current slide, the next slide and the notes.; Business Productivity Software
Pretexting: Inventing a story, such as posing as IT support, to get information.; Introduction to IT Network and Security - Foundations Network and Security - Applications
Preventive action: Action that removes the cause of a potential problem elsewhere.; Problem Solving for Technology Business Problems
Preventive and detective controls: Controls that stop incidents, and controls that find them; Network and Security - Foundations
Preventive measure: A change made after a fix so the same problem does not happen again.; Networks
Preventive measures: Steps that stop the problem from returning.; IT Foundations
Primary group: The group a user's new files belong to by default; Linux Foundations
Primary key: A column that uniquely identifies each row in a table.; Introduction to IT Data Management - Foundations
Primary source: The original evidence, such as official documentation, data or research, rather than a summary of it.; Introduction to IT
Print spooler: The Windows service that queues print jobs.; IT Foundations
Print Titles: Rows or columns repeated on every printed page.; Fundamentals of Spreadsheets and Data Presentations
Privacy by design: Building privacy protections into a system from the start.; Digital Transformation in the Enterprise Technology Governance
Privilege creep: Access that piles up as people change roles; Network and Security - Foundations Network and Security - Applications
Problem management: Finding and removing the root cause of repeated incidents.; Introduction to IT
Problem statement: A measured description of the gap between current and desired state, with impact and scope.; Problem Solving for Technology Business Problems
Procedure: Step-by-step instructions for a task; Network and Security - Foundations Network and Security - Applications
Process: A running instance of a program; Linux Foundations
Product Backlog refinement: Ongoing work to break down, describe, order and size backlog items.; Agile Methodology
Product Goal: The long-term objective of the product; the Product Backlog's commitment.; Agile Methodology
Productivity suite: A bundle of standard work applications, such as Microsoft 365 or Google Workspace.; Business Productivity Software
Project (π): Relational operation that keeps chosen columns.; Data Management - Foundations
Project life cycle: The phases of a project: initiating, planning, executing, monitoring and controlling, closing.; Introduction to IT
Prompt: The input given to a generative model: instructions, context, data and examples.; Practical Applications of Prompt
Prompt chaining: Linking prompts so each output becomes the next input.; Practical Applications of Prompt
Prompt engineering: Designing, testing and refining prompts to get targeted, reliable output.; Practical Applications of Prompt
Prompt fluency: The skill of using prompts effectively across tasks, media and tools.; Practical Applications of Prompt
Prompt injection: Instructions hidden in input data that try to override the user's or developer's instructions.; Practical Applications of Prompt Network and Security - Applications
Prompt pattern: A reusable prompt structure that solves a recurring problem in working with LLMs.; Practical Applications of Prompt
Proof of concept: Small test showing a technology can work for the use case.; Digital Transformation in the Enterprise
Proprietary (closed source): Software whose code the vendor owns; you buy a license to use it.; Introduction to IT
Protocol data unit (PDU): The name for data at a given layer: bits, frames, packets, segments or datagrams, and data.; Networks
Provider: Under the EU AI Act, the party that develops an AI system and places it on the market under its name.; Data and AI Strategy
Proxy server: A server that forwards users' web requests and can cache pages or block sites.; Introduction to IT
Pseudo-device: A device file with no hardware behind it, such as /dev/null; Linux Foundations
Psychological safety: A shared belief that the team is safe for interpersonal risk taking.; Agile Methodology Agile Processes and Culture in Technology Leading a Technology Transformation
Publish/subscribe: A messaging pattern where one published message reaches every subscriber.; Cloud Foundations
Pull system: Work is started only when capacity is free, not pushed in on a schedule.; Agile Methodology
Pulse survey: A short, frequent survey to track sentiment and readiness during change.; Leading a Technology Transformation
PXE (Preboot eXecution Environment): Firmware feature that lets a PC boot an installer or image from a server over the network.; IT Applications
PyPI: Python Package Index, source of pip installs.; Python for IT Automation

Q

QoS: Quality of service: rules that prioritize time-sensitive traffic such as voice.; IT Foundations
Quarantine: Isolating an infected system or file so it cannot spread or cause harm.; IT Applications
Quoting: Using quotes or backslashes to control how the shell reads text; Linux Foundations

R

Race condition (TOCTOU): A flaw where the state changes between checking a resource and using it.; Network and Security - Applications
RACI: Responsibility assignment matrix: Responsible, Accountable, Consulted, Informed.; Project Management Technology Governance Problem Solving for Technology Business Problems
Rack unit (U): The height unit for rack equipment: 1.75 inches.; Networks
RADIUS: A standard protocol for central authentication, authorization, and accounting.; IT Applications Network and Security - Foundations
RAG: Retrieval-augmented generation: a model answers from documents retrieved at query time.; Data and AI Strategy
RAID log: Register of risks, assumptions, issues and dependencies.; Leading a Technology Transformation
raise: Statement that throws an exception.; Foundations of Programming (Python)
raise_for_status(): Raises HTTPError for 4xx and 5xx responses.; Python for IT Automation
Range: A rectangular group of cells, such as A1:D20.; Fundamentals of Spreadsheets and Data Presentations
Ransomware: Malware that encrypts or locks data and demands payment.; Introduction to IT IT Applications Network and Security - Foundations+1
Rapid elasticity: Resources that scale out and in quickly with demand.; Introduction to IT Network and Security - Foundations
RBAC: Access control in which permissions follow job roles; Network and Security - Foundations Network and Security - Applications
RDP: Remote Desktop Protocol: Microsoft's protocol for remote graphical control of Windows, port 3389.; IT Applications
Readiness (situational leadership): A follower's ability and willingness for a specific task.; Information Technology Management and Leadership
Recurring event: A calendar event that repeats on a schedule.; Business Productivity Software
Recursive: Acting on a directory and everything inside it; Linux Foundations
Recursive resolver: A DNS server that performs the full lookup on a client's behalf.; Networks
Redirection: Sending a stream to or from a file instead of the terminal; Linux Foundations
Referential integrity: The rule that every non-NULL foreign key value matches an existing primary key value.; Data Management - Foundations
Refresh rate: How often the image is redrawn each second, in hertz.; IT Foundations
Region: A geographic area that contains multiple Availability Zones.; Cloud Foundations
Registry: The database where Windows and applications store their settings.; IT Applications
Regular expression: A pattern that describes text to match; Linux Foundations Python for IT Automation
Rehost: Lift and shift: moving an application to the cloud without changes.; Cloud Foundations
Relation: The formal name for a table.; Data Management - Foundations
Relational algebra: The set of operations on tables that SQL is based on.; Data Management - Foundations
Relational database: A database that stores data in related tables of rows and columns.; Introduction to IT
Relative path: A path that starts from the current directory; Linux Foundations
Relative reference: A reference that shifts when the formula is copied, such as A1.; Fundamentals of Spreadsheets and Data Presentations
Release notes: A vendor's official description of what changed in a software version.; Introduction to IT
Remote: The server copy of a repository (origin).; Python for IT Automation
Remote wipe: Erasing a lost or stolen device over the network.; IT Applications
Remove Duplicates: Deletes rows that repeat others in the chosen columns.; Fundamentals of Spreadsheets and Data Presentations
REPL: Read, evaluate, print, loop: the >>> prompt.; Foundations of Programming (Python)
Repository: A distribution's online, signed collection of packages; Linux Foundations Python for IT Automation
Requirement: Something the solution must do or support.; Business Productivity Software
Requirements traceability matrix: Table linking requirements to their origin and to the deliverables and tests that satisfy them.; Project Management
requirements.txt: List of packages and versions for pip install -r.; Python for IT Automation
Reserved Instance: A 1- or 3-year commitment to an instance configuration in exchange for a discount.; Cloud Foundations
Reserved word: A word that SQL uses as a keyword, such as ORDER or SELECT; avoid it as a name.; Data Management - Applications
Residual risk: The risk that remains after controls are applied.; Network and Security - Applications Technology Governance Risk Management and Information Technology
Resolver: The part of the system that turns names into addresses; Linux Foundations
Resource path: The part of a URL after the domain name that locates the file on the server.; Introduction to IT
REST API: HTTP interface where URLs name resources and methods name actions.; Python for IT Automation
Retention policy: Rules for how long records must be kept and when they are deleted.; Business Productivity Software
Retry: Repeating a failed action a limited number of times.; Python for IT Automation
Return code: The command's exit status.; Python for IT Automation
Return value: What a call evaluates to; None if no return runs.; Foundations of Programming (Python)
RFC 1918: The standard that reserves 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16 for private networks.; Networks
RFID: Radio-frequency identification: reading tags by radio without line of sight.; IT Foundations
Right to be forgotten: A person's right to have their personal data erased.; Network and Security - Applications
Right-to-audit clause: A contract term that lets the customer inspect the vendor's controls.; Network and Security - Applications
Rightsizing: Matching resource type and size to actual usage.; Cloud Foundations
Risk: The likelihood that a threat exploits a vulnerability, combined with the impact.; Introduction to IT Networks
Risk appetite: How much risk the organization is willing to take to reach its goals.; Network and Security - Applications Information Technology Management and Leadership Technology Governance+1
Risk assessment: Listing assets, threats and vulnerabilities and rating each risk by likelihood and impact.; Introduction to IT
Risk owner: The person with authority and accountability to manage a given risk.; Risk Management and Information Technology
Risk reduction per dollar: ALE reduced / annual control cost; ranks competing security investments.; Cybersecurity Strategy
Risk register: The record of identified risks, their ratings and responses; Network and Security - Foundations Network and Security - Applications Project Management+2
Risk response: How an organization handles a risk: mitigate, transfer, avoid or accept.; Introduction to IT
Risk tolerance: Acceptable, measurable deviation from the appetite for a specific objective.; Risk Management and Information Technology
Risk transfer: Shifting the financial consequence of a risk to another party, usually insurance or contract.; Risk Management and Information Technology
RMM: Remote monitoring and management: agent-based software for managing many devices from one console.; IT Applications
Roadmap: Time-phased plan of initiatives, milestones and owners.; Digital Transformation in the Enterprise
Roaming profile: A user profile stored on a server and copied to whatever PC the user signs in to.; IT Applications
ROI: Return on investment: net benefit divided by cost.; Financial Planning for IT Professionals
Rollback plan: Steps to undo a change if it fails.; IT Applications
Rolling forecast: A forecast updated at regular intervals that always looks a fixed period ahead.; Financial Planning for IT Professionals
Rolling release: A distribution updated continuously instead of in numbered versions; Linux Foundations
Root: The superuser account, user ID 0; Linux Foundations
Root cause analysis: Finding the underlying reason an incident happened.; Network and Security - Applications
Root cause analysis (RCA): A structured method to find the underlying cause of a problem so it does not recur.; Problem Solving for Technology Business Problems
Root directory: /, the top of the single Linux directory tree; Linux Foundations
Root of trust: The starting point trusted without outside proof, such as a root CA certificate or a TPM.; Network and Security - Applications
Root user: The identity created with the AWS account; full access that cannot be restricted by IAM policies.; Cloud Foundations
Rootkit: Malware that hides deep in a system to keep an attacker's access.; Introduction to IT IT Applications Network and Security - Applications
ROSI: Return on security investment: net risk reduction minus control cost, divided by control cost.; Cybersecurity Strategy
Router: Connects networks and forwards traffic using IP addresses.; Introduction to IT
Router on a stick: Routing between VLANs on one physical router interface split into 802.1Q subinterfaces.; Networks
Routing table: The list of networks a device knows and where to send traffic for each; Network and Security - Foundations Networks
RPA: Robotic process automation: software bots that perform rule-based computer tasks.; Introduction to IT
RPO: Recovery point objective: the point in time to which data must be recovered; the acceptable data loss.; Introduction to IT Network and Security - Foundations Networks+3
RPO and RTO: Recovery point objective (acceptable data loss) and recovery time objective (acceptable downtime).; IT Applications
RSSI: Received signal strength indicator: Wi-Fi signal strength in dBm, closer to zero being stronger.; Networks
RTO: Recovery time objective: the longest a system may take to be restored.; Introduction to IT Network and Security - Foundations Networks+3
RTO / RPO: Recovery time objective (max downtime) and recovery point objective (max data loss).; Cloud Strategy
Rules of engagement: The agreed scope, timing and limits of a security test.; Network and Security - Applications
Run the business (RTB): Spend to operate and maintain current services.; Financial Planning for IT Professionals
Run-rate: Current monthly spend × 12; the annualized cost at today's level.; Financial Planning for IT Professionals
Runbook: Step-by-step instructions for a routine operational task, often automated.; Network and Security - Applications

S

S.M.A.R.T.: Self-monitoring, analysis and reporting technology: a drive's own health reporting.; IT Foundations
SaaS: Software as a service: software used over the internet while the provider runs everything.; Introduction to IT Introduction to IT IT Foundations+1
SaaS, PaaS, IaaS: Cloud service models, from the provider managing the most to the customer managing the most; Network and Security - Foundations
SAE: Simultaneous Authentication of Equals: the WPA3 Personal handshake that resists offline password guessing.; IT Applications Network and Security - Foundations Network and Security - Applications
Safe Mode: A Windows startup with only essential drivers and services, used to isolate problems.; IT Applications
Salt: Random data added to a password before hashing; Network and Security - Foundations Network and Security - Applications
SAML: XML-based standard for single sign-on between an identity provider and a service provider.; Network and Security - Applications
SAN: Storage area network: a dedicated network giving servers block-level storage.; IT Foundations
Sandboxing: Running untrusted code in an isolated environment.; Network and Security - Applications
SAST and DAST: Static analysis of source code, and dynamic testing of the running application.; Network and Security - Applications
SAVEPOINT: A named point inside a transaction that you can roll back to.; Data Management - Applications
Savings Plan: A 1- or 3-year commitment to an hourly spend in exchange for lower prices.; Cloud Foundations
SCADA: Supervisory control and data acquisition: systems that monitor and control industrial processes.; Network and Security - Applications
Scalar function: A function that returns one value for each row, such as UPPER or ROUND.; Data Management - Applications
Scalar subquery: A subquery that returns exactly one value.; Data Management - Applications
Scareware: Fake security warnings designed to frighten users into paying or installing malware.; IT Applications
Scope: The breadth and boundaries of what the response should cover.; Practical Applications of Prompt Foundations of Programming (Python)
Scope baseline: Approved scope statement, WBS and WBS dictionary.; Project Management
Scope creep: Work added to a project without adding time or budget, raising cost and causing delays.; Introduction to IT
Screened subnet: An isolated segment for servers that the internet must reach; formerly called a DMZ.; IT Applications Networks
Screened subnet (DMZ): A zone for internet-facing systems, separated from the internal network.; Network and Security - Applications
Script: A text file of commands run by an interpreter to automate a task.; IT Applications Foundations of Programming (Python)
Scrum: An Agile framework that delivers work in Sprints with set roles and events.; Introduction to IT
Scrumban: A hybrid using Scrum's structure with Kanban's flow practices.; Agile Methodology
SD-WAN: Software-defined management of the links between sites, steering traffic by application over any mix of transports.; Networks
SDLC: Software development life cycle: planning, requirements, design, development, testing, deployment and maintenance.; Introduction to IT
SDS: Safety data sheet: handling and disposal information for a hazardous material.; IT Foundations
SDS (MSDS): Safety data sheet describing a product's hazards, handling, and disposal.; IT Applications
Secondary axis: A second value axis for a series with a different scale.; Fundamentals of Spreadsheets and Data Presentations
Section: A numbered part of the manual, such as 1 for commands or 5 for file formats; Linux Foundations
Secure baseline: A documented, tested secure configuration for a type of system.; Network and Security - Applications
Secure Boot: A UEFI feature that runs only signed boot loaders.; IT Foundations
Secured print: A job held at the printer until the user releases it with a PIN or badge.; IT Foundations
Security analyst: Monitors for threats and responds to security incidents.; Introduction to IT
Security champion: A team member trained to promote secure practice and act as liaison to the security team.; Cybersecurity Strategy
Security group: A stateful firewall attached to an instance; allow rules only.; Cloud Foundations
Security in the cloud: The customer's part: protecting what they build and store on AWS.; Cloud Foundations
Security of the cloud: AWS's part: protecting the infrastructure that runs AWS services.; Cloud Foundations
Security roadmap: Time-phased plan of initiatives that moves the program from current to target state.; Cybersecurity Strategy
Segregation of duties: Splitting a task so one person cannot both perform and approve it.; Technology Governance
Select (σ): Relational operation that keeps rows meeting a condition.; Data Management - Foundations
Selective wipe: Removing only company apps and data from a device, leaving personal data alone.; IT Foundations
Self-join: A join of a table with itself using two aliases.; Data Management - Applications
Self-managing team: A team that decides internally who does what, when and how.; Agile Methodology
SELinux: Mandatory access control for Linux.; Network and Security - Applications
Semantic HTML: Elements chosen for meaning (nav, main, button), not appearance.; Web Design Fundamentals
Sensitivity analysis: Testing how results change as one assumption changes.; Financial Planning for IT Professionals
Sensitivity label: A marking applied to files or emails that can restrict how they are shared.; Business Productivity Software
Separation of duties: Splitting a critical task so one person cannot complete it alone; Network and Security - Foundations
Separation pad: The part that lets only one sheet feed at a time.; IT Foundations
Serialization: Converting objects to text (dump) and back (load).; Python for IT Automation
Servant leadership: Leadership that puts the growth and needs of the team first so the team can perform.; Agile Processes and Culture in Technology
Server: A computer, physical or virtual, that provides services to other devices.; Introduction to IT
Serverless: Code that runs on demand without the customer managing servers.; Network and Security - Applications Cloud Foundations
Service desk: The single point of contact where users report problems and request help.; Introduction to IT
Service level agreement (SLA): A documented agreement between a service provider and a customer that identifies both services required and the expected level of service.; Business of IT - Applications
Service relationship: Cooperation between a service provider and a service consumer.; Business of IT - Applications
Service value system: ITIL 4 model of how components work together to turn demand into value.; Technology Governance
Set: Unordered collection of unique values.; Foundations of Programming (Python)
SET NULL: Referential action that sets child foreign keys to NULL when the parent is deleted or changed.; Data Management - Foundations
SFW query: A SELECT-FROM-WHERE query on one table.; Data Management - Applications
Shadow AI: AI tools used without approval or governance, often public GenAI services.; Data and AI Strategy
Shadow IT: Technology used for work without the IT department's approval.; Business Productivity Software Information Technology Management and Leadership Cybersecurity Strategy
Share link: A link that lets others watch a video, controlled by viewing permissions.; Business Productivity Software
Shared control: A control both parties apply in their own layer, such as patch management.; Cloud Foundations
Shared responsibility model: The split of security duties between the cloud provider and the customer.; Introduction to IT Network and Security - Foundations Network and Security - Applications+3
Shareware: Software offered free for a trial period, after which you pay to keep using it.; Introduction to IT
Shebang: The first line of a Linux script, such as #!/bin/bash, naming the interpreter to use.; IT Applications Linux Foundations Foundations of Programming (Python)
Shell: The program that reads and runs commands; Bash on most distributions; Linux Foundations
Short-term win: Early visible result that builds credibility for the change.; Digital Transformation in the Enterprise
SHOW CREATE TABLE: Displays the full CREATE TABLE statement MySQL stored for a table.; Data Management - Applications
Show Values As: Displays values as percentages, running totals or differences.; Fundamentals of Spreadsheets and Data Presentations
Showback: Reporting IT consumption and cost to business units without billing them.; Financial Planning for IT Professionals
shutil: High-level file operations: copy, move, archive, remove trees.; Python for IT Automation
Sideloading: Installing an app from outside the official app store.; IT Applications Network and Security - Applications
SIEM: Security information and event management: a system that collects and correlates logs to raise security alerts.; Networks Network and Security - Applications
Signature-based detection: Matching traffic or files against known attack patterns.; Network and Security - Applications
Simplicity (agile): Maximizing the amount of work not done.; Agile Methodology
Single loss expectancy (SLE): Asset value times exposure factor: the cost of one occurrence.; Network and Security - Applications
Single point of failure: One component whose failure stops the whole system; Network and Security - Foundations Information Technology Management and Leadership
Single sign-on (SSO): One sign-in that grants access to many applications.; IT Applications
Single source of truth: One official location for a piece of information, linked from everywhere else.; Business Productivity Software
Single-mode fiber: Thin-core fiber lit by a laser for long distances.; IT Foundations Network and Security - Foundations Networks
Site-to-site VPN: A permanent encrypted tunnel that joins two networks through their gateways.; Networks
Skills gap: Difference between the skills a strategy needs and the skills the team has.; Information Technology Management and Leadership
SLA: Service level agreement: a written target for a service, such as response or uptime.; Introduction to IT IT Applications Networks+2
SLAAC: Stateless address autoconfiguration: IPv6 hosts building their own addresses from the router's prefix.; Networks Linux Foundations
SLAT: Second-level address translation: a CPU feature Hyper-V requires.; IT Foundations
SLE: Single loss expectancy: AV × EF, the loss from one event.; Risk Management and Information Technology
Slice: s[start:stop:step]; stop is excluded.; Foundations of Programming (Python)
Slicer: A set of buttons that filters one or more PivotTables or tables.; Fundamentals of Spreadsheets and Data Presentations
Slide master: PowerPoint's master layout that controls fonts, colors and placeholders on every slide.; Business Productivity Software
SLO: Service level objective: the internal reliability target, usually stricter than the contractual SLA.; Cloud Strategy
SMART goal: A goal that is specific, measurable, achievable, relevant and time-bound.; Business Productivity Software Information Technology Management and Leadership
Smishing: Phishing by text message.; Introduction to IT
SMTP: Protocol for sending mail.; Python for IT Automation
SNMP trap: An unsolicited alert an SNMP agent sends to the manager, on UDP 162.; Networks
SOAR: Security orchestration, automation and response: automated playbooks across tools.; Network and Security - Applications
SOC 2 Type II: Auditor's report on the design and operating effectiveness of a service organization's controls over a period.; Risk Management and Information Technology
Social engineering: Tricking people into giving up access or information.; Introduction to IT
Social responsibility: Accountability for an organization's effects on society and the environment.; Technology Governance
SODIMM: Small outline dual in-line memory module: the smaller RAM module used in laptops and small PCs.; IT Foundations
Software-defined networking (SDN): Separating the control plane from the data plane so a central controller programs the network.; Networks
SOP: Standard operating procedure: written steps for doing a routine task the same way every time.; IT Applications
Sort: Reorders whole rows by one or more columns.; Fundamentals of Spreadsheets and Data Presentations
SOW: Statement of work: the deliverables, schedule and price for a specific project.; Network and Security - Applications
Spanning Tree Protocol (STP): A protocol that blocks redundant switch paths to prevent loops and broadcast storms.; Networks
Sparkline: A small chart inside one cell showing a trend.; Fundamentals of Spreadsheets and Data Presentations
Speaker notes: Notes attached to each slide for the presenter, not shown to the audience.; Business Productivity Software Technical Communication
Spear phishing: Phishing aimed at a specific person using details about them.; Introduction to IT Network and Security - Applications
Specificity: How precisely the prompt states requirements: details, format, audience, measures.; Practical Applications of Prompt
Speech to text: Transcribing spoken audio into text.; Practical Applications of Prompt
SPF, DKIM and DMARC: DNS-based email authentication: allowed senders, message signatures, and the policy for failures.; Network and Security - Applications
Spine and leaf: A data center design in which every leaf switch connects to every spine switch.; Networks
Split tunnel: A VPN setting that sends only company-bound traffic through the tunnel.; Networks Network and Security - Applications
Sponsor: The senior leader who authorizes, funds and visibly leads the change.; Leading a Technology Transformation
Spot Instance: Spare capacity at a deep discount that AWS can reclaim with two minutes' notice.; Cloud Foundations
Sprint: A Scrum work cycle of one month or less.; Introduction to IT
Sprint Goal: The single objective for the Sprint, created in Sprint Planning.; Agile Methodology
SQL: Structured Query Language, used to query and manage relational data.; Introduction to IT
SQL injection: Input that is interpreted as part of a database query.; Network and Security - Applications
ss: The command that lists sockets: connections and listening ports; Linux Foundations
SSE: Security Service Edge: cloud-delivered security services such as a secure web gateway, CASB and ZTNA.; Network and Security - Applications
SSH: Secure Shell: encrypted remote command-line access, port 22.; IT Applications Linux Foundations Python for IT Automation
SSID: The name of a wireless network.; Networks
SSO: One login that gives access to many applications; Network and Security - Foundations
SSOT: Single source of truth: one authoritative, governed version of a data entity.; Data and AI Strategy
Staff augmentation: Temporary external staff working under the organization's direction.; Technology Governance
Stage gate: A funding checkpoint where a project continues only if it meets set criteria.; Financial Planning for IT Professionals Leading a Technology Transformation
Stakeholder: Anyone affected by or interested in the work, such as a manager, teammate, client or new hire.; Business Productivity Software Agile Methodology Project Management
Stakeholder analysis: Identifying who is affected or has influence, and planning engagement.; Problem Solving for Technology Business Problems
Stakeholder salience: Priority of a stakeholder from three attributes: power, legitimacy, urgency.; Leading a Technology Transformation
Standard: A document of specific requirements to meet; Network and Security - Foundations Network and Security - Applications
Standard contractual clauses (SCCs): EU-approved contract terms that permit personal data transfers outside the EEA.; Cloud Strategy
Standard user: An account that can use the computer but cannot change system-wide settings without an administrator.; IT Applications
START TRANSACTION: Begins a group of statements that commit or roll back together.; Data Management - Applications
STARTTLS: Upgrades a plain connection to TLS.; Python for IT Automation
Startup Repair: A WinRE tool that automatically fixes common problems preventing Windows from starting.; IT Applications
Stateful firewall: A firewall that tracks connections and allows replies to traffic started inside; Network and Security - Foundations Networks Network and Security - Applications
Statement: A complete SQL command, ended with a semicolon.; Data Management - Foundations
stdin, stdout, stderr: Standard input (0), standard output (1) and standard error (2); Linux Foundations
Steering committee: Business and IT leaders who approve and prioritize IT investments.; Information Technology Management and Leadership Leading a Technology Transformation
Step into: Enter the function called on the current line.; Foundations of Programming (Python)
Step over: Run the current line, including any call, then pause.; Foundations of Programming (Python)
Sticky bit: A directory permission that lets users delete only their own files; Linux Foundations
Stop code: The error code on a Windows crash screen.; IT Foundations IT Applications
Story point: A relative unit of size for backlog items.; Agile Methodology
STP: Shielded twisted pair: copper cable with shielding against interference.; IT Foundations
Stream-aligned team: A team aligned to a single flow of business value, able to deliver it end to end.; Agile Processes and Culture in Technology
Structured reference: A reference by table and column name, such as Sales[Revenue].; Fundamentals of Spreadsheets and Data Presentations
su: Switches to another user, using that user's password; Linux Foundations
Subnet: A range of IP addresses in one Availability Zone.; Cloud Foundations
Subnet mask: Shows which part of an IPv4 address is the network; 255.255.255.0 is /24.; IT Foundations Network and Security - Foundations Networks
subprocess.run: Runs an external command and returns a CompletedProcess.; Python for IT Automation
Subquery: A query nested inside another statement.; Data Management - Foundations Data Management - Applications
SUBTOTAL: Calculates on visible rows only, such as =SUBTOTAL(9, range) for a sum.; Fundamentals of Spreadsheets and Data Presentations
Success criteria: Measurable standards a response must meet, set before testing.; Practical Applications of Prompt
sudo: Linux and macOS command that runs a single command with root privileges.; IT Applications Linux Foundations
Suggesting mode: Google Docs' mode that turns edits into suggestions for the owner to review.; Business Productivity Software
Supertype and subtype: A general entity and the more specific entities that inherit its attributes.; Data Management - Foundations
Supply chain attack: Compromising a target through a trusted supplier, provider or update.; Network and Security - Applications
Surrogate key: An artificial identifier with no business meaning.; Data Management - Foundations
Sustainable pace: A workload the team can keep up indefinitely without burnout.; Agile Methodology
Switch: Connects devices within a LAN using MAC addresses.; Introduction to IT
Switch Row/Column: Swaps which data is plotted as series and which as categories.; Fundamentals of Spreadsheets and Data Presentations
Sycophancy: A model's tendency to agree with the user, including false premises.; Practical Applications of Prompt
Symbolic link: A file that points to another path; Linux Foundations
Symbolic mode: Permissions changed with letters, such as u+x; Linux Foundations
Symmetric encryption: One shared key for encryption and decryption; Network and Security - Foundations Network and Security - Applications
SYN flood: Opening many half-finished TCP handshakes to exhaust a server; Network and Security - Foundations
Synchronization: Keeping the same mail, contacts, calendar and files across devices and the cloud.; IT Foundations
Synchronous communication: Communication in real time, such as a meeting or phone call.; Business Productivity Software
SYNOPSIS: The part of a man page that shows the command's syntax; Linux Foundations
Synthetic full backup: A full backup assembled from earlier backups instead of being read again from the source.; IT Applications
System Restore: Rolls system files, drivers, and settings back to a restore point without changing personal files.; IT Applications
System software: Software that runs the computer: operating systems, firmware, drivers and utilities.; Introduction to IT
System user: An account that runs a service and usually cannot log in; Linux Foundations
systemd unit: Something systemd manages, such as a service; Linux Foundations
Systems administrator: Runs and maintains servers, operating systems and user accounts.; Introduction to IT

T

T568B: The common RJ45 pin order starting white-orange, orange.; IT Foundations
Table alias: A short name for a table within one query.; Data Management - Applications
Table cluster: Rows of related tables stored together in the same blocks.; Data Management - Foundations
Table scan: Reading every block of a table to answer a query.; Data Management - Foundations
Table-level constraint: A constraint written after the columns; needed for multi-column rules.; Data Management - Foundations
Tablespace: A storage area that holds one or more tables.; Data Management - Foundations
Tabletop exercise: A discussion-based walk-through of a disaster scenario to test a plan.; Networks Network and Security - Applications Risk Management and Information Technology+1
TACACS+: A Cisco-developed AAA protocol over TCP 49 that encrypts the entire exchange.; IT Applications Networks
Tailgating: Following an authorized person through a secured door.; Introduction to IT Network and Security - Foundations Networks+1
Tarball: A tar archive, often compressed, such as backup.tar.gz; Linux Foundations
Task: A specific action with a clear finish, an owner and a due date.; Business Productivity Software
TBM: Technology Business Management: a framework and taxonomy for managing IT costs and value.; Financial Planning for IT Professionals
TCO: Total cost of ownership: the full cost of an option over time, including hidden costs.; Cloud Foundations Information Technology Management and Leadership Technology Governance+2
TCP: Transmission Control Protocol: delivers data reliably and in order.; Introduction to IT IT Foundations
TCP/IP model: The four-layer model the internet's protocols are built on; Network and Security - Foundations
Technical account manager (TAM): A designated AWS contact who knows a customer's environment; included in Enterprise Support and Unified Operations.; Cloud Foundations
Technical control: A safeguard carried out by hardware or software.; Network and Security - Applications
Technical debt: The future cost of shortcuts and outdated systems that must eventually be fixed.; Introduction to IT Information Technology Management and Leadership
Technology infrastructure: All the hardware, software, networks, data, facilities, people and processes an organization uses to run its digital work.; Introduction to IT
Technology roadmap: An organization's plan for which technologies it will adopt, upgrade or retire, and when.; Introduction to IT Leading a Technology Transformation
Telnet: Unencrypted remote shell, TCP 23.; Python for IT Automation
Template: A reusable starting file with standard layout and sections.; Business Productivity Software
Test: A condition in [ ], such as -f for an existing file; Linux Foundations
Test case: An input with its expected output.; Foundations of Programming (Python)
Tethering: Sharing a phone's cellular data connection with another device over USB, Bluetooth or Wi-Fi.; IT Foundations
TEVV: Test, evaluation, verification and validation of AI systems.; Data and AI Strategy
Text to Columns: Splits one column into several at a delimiter or fixed width.; Fundamentals of Spreadsheets and Data Presentations
Text to speech (TTS): Generating spoken audio from text.; Practical Applications of Prompt
Theory of probable cause: Your best explanation of the problem, tested before you act on it.; IT Foundations Networks
Thermal throttling: The CPU slowing itself down to avoid overheating.; IT Foundations
Threat: Anything that could exploit a vulnerability and cause harm.; Introduction to IT Network and Security - Foundations
Threat actor: A person or group that may carry out an attack.; Network and Security - Applications
Threat detection: Watching logs and activity for signs of an attack in progress.; Cloud Foundations
Threat hunting: Proactively searching for attackers who have not triggered alerts.; Network and Security - Applications
Threat source: The actor or condition that can cause harm: adversarial, accidental, structural, environmental.; Risk Management and Information Technology
Threat vector: The path an attacker uses to reach a target.; Network and Security - Applications
Three Lines Model: IIA model: first line owns risk, second line oversees, third line (audit) assures.; Risk Management and Information Technology
Three-way handshake: SYN, SYN-ACK, ACK: how TCP opens a session.; IT Foundations Network and Security - Foundations Networks
Throughput: The data rate actually achieved, as opposed to the link's rated bandwidth.; Networks
Time blocking: Reserving calendar time for specific focused work.; Business Productivity Software
Time drift: A computer clock gradually moving away from the correct time.; IT Applications
Time Machine: The backup feature built into macOS.; IT Applications
TIME model: Gartner's application rationalization grid: Tolerate, Invest, Migrate, Eliminate.; Leading a Technology Transformation
Timestamped backup: Backup named with date and time so runs never overwrite.; Python for IT Automation
TLS: Transport Layer Security: the encryption behind HTTPS and other secure protocols.; IT Foundations Network and Security - Foundations
Token: The unit a model reads and writes; a word or part of a word.; Practical Applications of Prompt
Tokenization: Replacing a sensitive value with a random token, with the real value kept in a secure vault.; Network and Security - Applications
Toner probe: A tone generator and probe used to trace cables.; IT Foundations Networks
Topology: The layout of a network's connections, such as bus, star, ring or mesh.; Introduction to IT Network and Security - Foundations
Total float: Time an activity can slip without delaying project finish.; Project Management
TOTP: Time-based one-time password: a short code that changes every few seconds, usually 30.; IT Applications Network and Security - Applications
TPM: Trusted Platform Module: hardware that stores keys and checks boot integrity.; IT Foundations Network and Security - Applications
TPM (Trusted Platform Module): A security chip, or firmware equivalent, that stores encryption keys and checks boot integrity.; IT Applications
TPRM: Third-party risk management: assessing and monitoring vendors across their lifecycle.; Risk Management and Information Technology
Traceback: Call stack printed when an exception is not handled; read bottom up.; Foundations of Programming (Python)
traceroute / tracert: A tool that lists each router hop to a destination by sending probes with increasing TTL values.; Networks
Track Changes: Word's feature that records edits as markup for the author to accept or reject.; Business Productivity Software
Transaction: A group of statements that must all succeed or all fail.; Data Management - Foundations
Transactional database (OLTP): Handles day-to-day operations such as orders, payments and bookings.; Introduction to IT
Transactional leadership: Leading through exchanges: rewards for performance, correction for misses.; Information Technology Management and Leadership
Transceiver: A module that converts between electrical signals and light or radio, such as an SFP+ in a switch port.; Networks
Transit gateway: A routing hub joining many VPCs and on-premises links.; Cloud Applications
Transition architecture: An intermediate, stable state between baseline and target, delivering value on the way.; Leading a Technology Transformation
Transitive dependency: A non-key column depending on another non-key column; violates 3NF.; Data Management - Foundations
Trialability: How easily people can try an innovation on a limited basis.; Digital Transformation in the Enterprise
Triangulation: Confirming a finding with several independent sources.; Practical Applications of Prompt
TRIM: A command that tells an SSD which blocks are no longer in use, keeping it fast; SSDs are optimized with TRIM rather than defragmented.; IT Applications Fundamentals of Spreadsheets and Data Presentations
Triple constraint: Scope, time and cost: changing one forces a change in at least one other.; Introduction to IT
Trunk: A link that carries several VLANs, with each frame tagged by 802.1Q.; Networks
Truthy / falsy: How a value behaves in an if test.; Foundations of Programming (Python)
try/except: Runs code and handles named exceptions instead of crashing.; Foundations of Programming (Python)
Tuple: The formal name for a row.; Data Management - Foundations Foundations of Programming (Python)
Type 1 hypervisor: A hypervisor that runs directly on the hardware.; IT Foundations
Type 2 hypervisor: A hypervisor that runs as an application on a host operating system.; IT Foundations
Type conversion: Building a value of another type: int(), float(), str(), bool().; Foundations of Programming (Python)
Typosquatting: Registering look-alike domain names to catch mistyped addresses or fool users.; Network and Security - Applications

U

UDP: User Datagram Protocol: faster than TCP but doesn't guarantee delivery.; Introduction to IT IT Foundations
UID and GID: The numeric user ID and group ID; Linux Foundations
Ultimate utilization: Share of intended users who actually use the new way of working.; Leading a Technology Transformation
Unary relationship: A relationship between instances of the same entity.; Data Management - Foundations
UNC path: A network path in the form \\server\share.; IT Applications
Union-compatible: Having the same number of columns with compatible types in the same order.; Data Management - Foundations
UNIQUE: Constraint that prevents duplicate values in a column or column group.; Data Management - Foundations
Unit cost: Cost of an IT service divided by the units consumed.; Financial Planning for IT Professionals
Unit economics: Cost per unit of business output, such as per customer or per transaction.; Financial Planning for IT Professionals Cloud Strategy
Unpacking: Assigning a sequence's items to several names at once.; Foundations of Programming (Python)
Updatable view: A view whose rows map one-to-one to base table rows, so DML through it works.; Data Management - Applications
UPDATE: DML statement that changes values in existing rows.; Data Management - Foundations
UPDATE ... SET ... WHERE: Changes the listed columns in the rows that match.; Data Management - Applications
UPnP: A protocol that lets devices open router ports automatically.; IT Applications
UPS: Uninterruptible power supply: a battery unit that keeps equipment running through short power losses.; Introduction to IT IT Applications Networks
User acceptance testing (UAT): Real users confirming a system meets their needs before go-live.; Introduction to IT
User Account Control (UAC): The Windows prompt that asks for approval or credentials before changes that need administrator rights.; IT Applications
User story: A short description of a need from a user's view, with the value it brings.; Agile Methodology
Userspace: All the programs and libraries that run outside the kernel; Linux Foundations
USING: Join condition for columns that have the same name in both tables.; Data Management - Applications
Utility: Fit for purpose: what the service does.; Business of IT - Applications
UTP and STP: Unshielded and shielded twisted pair copper cable; Network and Security - Foundations

V

Value × feasibility: Prioritization that scores each use case on business value and ease of delivery, then ranks or plots them.; Data and AI Strategy
Value co-creation: Provider and consumer both contribute to the value; the provider does not deliver value alone.; Business of IT - Applications
Value Field Settings: Chooses the calculation and number format for a field in Values.; Fundamentals of Spreadsheets and Data Presentations
Value stream: A series of steps an organization takes to create and deliver products and services to consumers.; Business of IT - Applications
Value stream map: A diagram of every step from request to delivery, with wait and work times.; Agile Methodology
Variable: A named place to store a value in a script.; IT Applications Foundations of Programming (Python)
Variable expense: A cost that rises and falls with usage, instead of a fixed up-front purchase.; Cloud Foundations
Variance: Difference between actual and budgeted figures.; Financial Planning for IT Professionals
VDI: Virtual desktop infrastructure: desktops hosted as VMs and used remotely.; IT Foundations
Velocity: The amount of work a team completes per iteration.; Agile Methodology
Vendor lock-in: High cost or effort to move away from a provider because of proprietary services, data, contracts or skills.; Cloud Strategy
Vendor-neutral certification: A certification that covers concepts across products, such as those from CompTIA.; Introduction to IT
Version control: A system such as Git that records every change to files, with author and history.; Network and Security - Applications
Version history: The saved earlier versions of a file that can be viewed or restored.; Business Productivity Software
View: A named, stored query that can be selected from like a table.; Data Management - Foundations Data Management - Applications
Virtual appliance: Network software, such as a router or firewall, running as a virtual machine or cloud service instead of a dedicated box.; Networks
Virtual environment: Project-local interpreter and packages.; Python for IT Automation
Virtual machine (VM): A software-based computer running on a physical host through a hypervisor.; Introduction to IT
Virtual private cloud (VPC): A logically isolated private network inside a public cloud.; Networks
Virtual switch: Software switch that connects VMs to each other, the host or the physical network.; IT Foundations
Vishing: Phishing by voice call.; Introduction to IT
VLAN: A logical network created on a switch to separate traffic.; IT Foundations Network and Security - Foundations Networks
VLAN hopping: Reaching another VLAN's traffic by switch spoofing or double tagging.; Networks
VLOOKUP: Finds a value in a table's first column and returns a value from another column.; Fundamentals of Spreadsheets and Data Presentations
VLSM: Variable-length subnet masking: different subnet sizes inside one address block.; Networks
VM escape: Breaking out of a virtual machine to the hypervisor or other VMs.; Network and Security - Applications
Voice of the customer (VOC): Captured needs and expectations of the people served.; Problem Solving for Technology Business Problems
Volatile: Memory that loses its contents when power is off, such as RAM.; Introduction to IT
VPC: A logically isolated virtual network in AWS.; Cloud Foundations Cloud Applications
VPN: An encrypted connection across a public network to a private one.; Introduction to IT IT Applications Network and Security - Foundations
Vulnerability: A weakness that could be exploited.; Introduction to IT Network and Security - Foundations Cloud Foundations+1
VXLAN: A protocol that carries Layer 2 frames inside UDP to stretch segments across a Layer 3 network.; Networks

W

WACC: Weighted average cost of capital.; Financial Planning for IT Professionals
WAF: Web application firewall: filters HTTP traffic for web attacks.; Network and Security - Applications
Walkthrough: A recorded or live demonstration that steps through a process or piece of work.; Business Productivity Software
Warm site: An alternate site with equipment ready but data to restore, ready within days.; Introduction to IT
Warranty: Fit for use: how well it performs.; Business of IT - Applications
Waterfall: A sequential method in which each phase finishes before the next begins.; Introduction to IT Agile Methodology
Watering hole: Compromising a website that the target group is known to visit.; Network and Security - Applications
WCAG: Web Content Accessibility Guidelines, published by the W3C.; Web Design Fundamentals
Weak entity: An entity identified only together with its owner; its key includes the owner's key.; Data Management - Foundations
Web application firewall: A firewall that inspects HTTP and HTTPS requests and blocks malicious ones.; Cloud Foundations
Weekly review: A regular session to clear inboxes, update lists and plan the next week.; Business Productivity Software
Weighted decision matrix: Options scored against weighted criteria; highest total wins.; Problem Solving for Technology Business Problems
Weighted scoring: Ranking items by criteria scores multiplied by agreed weights.; Leading a Technology Transformation
Weighted scoring model: Decision matrix: criteria weights × option scores, summed per option.; Cloud Strategy
Well-known ports: Ports 0 to 1023, assigned to standard services; Network and Security - Foundations Networks
Westrum typology: Ron Westrum's classification of organizational culture by how information flows: pathological, bureaucratic, generative.; Agile Processes and Culture in Technology
Whaling: Spear phishing that targets executives.; Introduction to IT
WHERE clause: The condition each row must meet to be included.; Data Management - Foundations
Wi-Fi 6E: 802.11ax operating in the 6 GHz band.; IT Foundations
Wiki: A set of easily edited, linked pages for shared team knowledge.; Business Productivity Software
Wildcard certificate: A certificate for *.domain that covers one level of subdomains.; Network and Security - Applications
WinRE: Windows Recovery Environment: the built-in repair tools that run outside normal Windows.; IT Applications
WinRM: Windows Remote Management: the service behind PowerShell remoting, ports 5985 and 5986.; IT Applications
WIP limit: A cap on how many tasks can be in progress at once.; Business Productivity Software Agile Methodology
WISP: Wireless internet service provider: fixed wireless internet using antennas.; IT Foundations
with: Context manager that closes the file even after an error.; Foundations of Programming (Python)
WITH CHECK OPTION: Rejects inserts and updates through a view that would produce rows outside the view.; Data Management - Applications
Work package: Lowest WBS level, where cost and duration are estimated and managed.; Project Management
Workaround: A solution that reduces or eliminates the impact of an incident or problem for which a full resolution is not yet available.; Business of IT - Applications
Workbook: An Excel file containing one or more worksheets.; Fundamentals of Spreadsheets and Data Presentations
Workflow automation: Tools that perform routine steps automatically when something happens.; Business Productivity Software
Workgroup: A small peer network where each PC manages its own accounts.; IT Applications
Working agreement: Norms a team writes and agrees on for how it works together.; Agile Methodology
Working directory: Folder a terminal or program is in; relative file names resolve there.; Foundations of Programming (Python)
Workload: A set of components that together deliver business value, such as an application and its database.; Cloud Foundations
Worm: Malware that spreads across networks on its own; Network and Security - Foundations
WPA3: The current Wi-Fi security standard; its Personal mode uses SAE instead of a pre-shared key handshake.; IT Applications Networks
WSJF: Weighted shortest job first: cost of delay divided by job duration.; Agile Processes and Culture in Technology Leading a Technology Transformation
WSL: Windows Subsystem for Linux, which runs a Linux distribution inside Windows; Linux Foundations

X

XLOOKUP: A newer lookup with separate lookup and return ranges and exact match by default.; Fundamentals of Spreadsheets and Data Presentations

Z

Zero Trust: A security model that verifies every request instead of trusting anything inside the network.; IT Applications Network and Security - Foundations Networks+3
Zero-based budgeting: Building the budget from zero, justifying each line.; Financial Planning for IT Professionals
Zero-day: A vulnerability exploited before a fix is available.; Network and Security - Applications
Zero-shot prompting: Giving a task with no examples.; Practical Applications of Prompt
Zero-touch deployment: A new device configures itself from the cloud at first sign-in, with no technician handling it.; IT Applications
zip(): Pairs items from several sequences by position.; Foundations of Programming (Python)