🌎Glossary

This glossary contains definitions and explanations of acronyms and industry terms that you may encounter on the UI of Accessibility Tools, in the test cases, or in the suggested remediations.

Specific acronyms have been used to shorten the length of some sentences and make them more easily readable (for example, desc, info, or alt).

Term	Definition
<a> element (anchor element)	An HTML tag used to create hyperlinks. It allows users to navigate to other web pages, files, sections within a page, or other resources when they click or interact with it.
Alt text	A short text alternative with the alt attribute used on the <img> element. The value of this attribute is referred to as "alt text". When an image contains words that are important to understanding the content, the alt text should include those words. Different from aria-label because alt-text is used only on <img> elements.
aria-label	An HTML attribute used to give accessible, descriptive labels to HTML elements that otherwise lack visible labels. Part of the ARIA (Accessible Rich Internet Applications) specification, aria-label helps assistive technologies like screen readers identify and convey the purpose of a particular element to users with disabilities. For example, if an icon button has no visible text, adding aria-label="Submit Form" will let a screen reader announce "Submit Form" when it reaches the button, even though visually there is no text displayed. Different from Alt-text because aria-label is used on any type of graphics, not the <img> elements.
AT	Assistive technologies (ATs) are hardware and software tools that help people with disabilities access and interact with digital content and user interfaces. Common types of assistive technologies: Screen readers - read text aloud and provide navigation for blind/low vision users Screen magnifiers - enlarge screen content for low vision users Voice recognition software - allows input through speech Alternative keyboards - specialized keyboards for motor impairments Switch devices - single-button controls for users with limited mobility Eye-tracking systems - control interfaces through eye movement Cognitive support tools - help with memory, attention, or processing
ATAG	Authoring Tool Accessibility Guidelines, a set of standards to make the authoring tools themselves accessible (so that people with disabilities can create web content) and help authors create more accessible web content.
Captions	Text displayed on-screen in sync with audio during a video. Captions include spoken dialogue and relevant sounds (e.g., “door creaks” or “[music playing]”) to provide context for viewers who are deaf or hard of hearing. Captions appear in real time and are typically embedded in the video itself. Disambiguation: Transcriptions provide a complete, static text document, while captions are synchronized text displayed within video content.
cc	Closed captions display text on-screen in real time with video content, representing spoken dialogue, sound effects, and other relevant audio cues. They are primarily designed for people who are deaf or hard of hearing and can be turned on or off by the user, unlike open captions, which are permanently visible.
Change of context	Major changes in the content of a web page that, if made without user awareness, can disorient users who cannot view the entire page simultaneously. Examples: Opening a new window, tab, or pop-up Moving focus to a different component or significantly changing content layout Significantly altering the meaning of the web page Automatically submitting a form when a dropdown selection is made Opening a new window when a link is clicked without warning Automatically redirecting to a new page Dramatically changing page layout or navigation Moving focus to a different part of the page unexpectedly
Control	Elements that a user can click, tap, or interact with to carry out a specific action (e.g., buttons, navigation links, checkboxes, sliders; user uses them to submit a form, open a new page, toggle a setting).
CSV	Comma Separated Values. In Accessibility Tools, this is the format in which test results are exported. For more information, see ???.
dir (rtl / ltr)	Text direction (right-to-left/left-to-right)
DOM	Document Object Mode, a programming interface that represents the structure and content of a web page as a tree of objects. It allows developers to dynamically access, modify, add, or delete elements and content within a webpage using scripting languages like JavaScript.
Down events	Pointer interactions that occur when a pointing device (like a mouse button, finger on touchscreen, or stylus) is initially pressed down or makes contact, before being released. Examples: Pointerdown Mousedown Touchstart
em unit	EM units are a relative measurement in web design and typography, where 1 em equals the font size of the parent element. They are commonly used for scalable and responsive font sizes, spacing, and layout design. For example, if the parent font size is 16px, 2em will be 32px. Unlike absolute units like pixels, em allows designs to adapt dynamically by scaling relative to their context.
Form controls	Interactive elements on web pages that allow users to input data, make selections, or trigger actions within forms, such as: Text input Checkboxes Radio buttons Combo boxes List boxes Buttons
Glyphs	Visual representations, or shape of a character. For example, the Unicode characters U+0033 and U+04E0 both look like the number "3", yet the latter is actually a letter from the Cyrillic alphabet. α (Greek letter alpha), € (Euro currency symbol), ♦ (diamond suit symbol), ∞ (infinity symbol) and © (copyright symbol) are all glyphs.
Info	Information
Input	Fields where users enter information (text fields - for names, emails, etc., radio buttons, date pickers, dropdown menus). Used for gathering info from users - when creating accounts, searching for products, entering payment details.
ltr	Text direction left-to-right (dir attribute)
Motion actuation	A functionality triggered by device motion or user gestures (tilting, shaking, or moving a device) to control UI elements or activate features. Examples: Shaking a phone to undo text input Tilting a device to steer in a game Rotating a tablet to trigger screen orientation changes Moving a device to control navigation or scrolling Gesture-based controls using accelerometer/gyroscope data
Non-text elements	Any content that is not a sequence of characters that can be programmatically determined or where the sequence is not expressing something in human language. Examples: Images (photographs, illustrations, icons, and graphics), charts and graphs, diagrams, time-based media (audio/video content) and so on.
Non-text content	Any not written/readable content which still conveys meaning/important information (images, audio and video, interactive media - charts, graphs, maps, infographics -, user interface components - buttons, sliders, other controls). This content requires text alternatives or other forms of accommodation.
OS	Operating system, system software that manages computer hardware and software resources, and provides common services for computer programs.
PD	Programmatically determined means that information can be read and processed by software, particularly assistive technologies, through properly structured code and markup rather than relying solely on visual presentation. Examples: Form label association - Using <label for="email"> connected to <input id="email"> allows screen readers to programmatically understand that "Email Address" is the label for the input field, rather than just visually positioning text near the field. Heading structure - Using proper heading elements <h1>, <h2>, <h3> creates a programmatically determined hierarchy that assistive technologies can navigate, unlike just making text visually larger with CSS styling. Table headers - Using <th> elements with scope="col" or scope="row" programmatically identifies which cells are headers and their relationships to data cells, enabling screen readers to announce "Sales, Quarter 1: $50,000" instead of just reading disconnected numbers.
PDF	Portable Document Format, a file format for capturing and sending electronic documents in exactly the intended format. In WCAG, some test cases target PDF files.
Programmatically determined	Information—such as the name, role, or state of a user interface component—can be identified and processed by assistive technologies through code. Thus, screen readers and other tools can access and convey the purpose and function of elements (like form fields, buttons, or links) to users who rely on these technologies. For example, if a button’s role (e.g., “submit”) and name (e.g., “Submit Form”) are set in the code, a screen reader can automatically read these aloud, making the interface accessible.
rtl	Text direction right-to-left (dir attribute)
SMIL (1.0, 2.0, 2.1)	Synchronized Multimedia Integration Language 1.0. SMIL 1.0 provides a structured way to ensure multimedia content is accessible, aligning with WCAG requirements for synchronized alternatives like captions, audio descriptions, or text alternatives for time-based media. It is particularly useful in scenarios involving complex multimedia presentations.
Sticky content	Webpage elements that remain fixed in their position on the screen as users scroll, staying visible even when other content moves past them. Examples: Headers that stay at the top of the page while scrolling. Navigation menus that remain accessible. Footers that stick to the bottom of the viewport. Sidebar elements that follow the user down the page. Floating action buttons or chat widgets.
SVG	Scalable Vector Graphics, a vector format used in logos, icons, and illustrations that need to scale without losing quality. SVG files are small and perfect for responsive web design.
Test	In Accessibility Tools, a test is a specific evaluation method that determines whether web content meets a particular WCAG success criterion via test cases. Each test consists of multiple test cases (see definition below). In Accessibility Tools, WCAG tests are: Automated, using tools to check measurable criteria like contrast ratios Manual, requiring human judgment for content quality Read more about how to work with tests in Accessibility Tools here.
Test cases	Test cases are predefined steps, conditions, and expected results that assess accessibility features such as keyboard navigation, screen reader compatibility, color contrast ratios, alternative text presence and so on. Accessibility Tools include both automated and manual tests. Manual tests should be performed by qualified specialists. Depending on their status, test cases may be: Failed Passed Not run (“manual” as opposed to “non-automated”, they require human intervention) Inconclusive Read more about how to work with test cases in Accessibility Tools here.
Text alt	Text alternative, descriptive text that conveys the same essential information and function as non-text content (like images, videos, or audio) for users who cannot access the original content.
TOC	Table of Contents
Transcription, Transcript	A complete, written version of all spoken dialogue, sound effects, music cues, and relevant non-verbal information in audio or video content. They are often provided as separate text documents for audio-only content, such as podcasts, or as an additional accessibility feature for video content. Disambiguation: Transcriptions provide a complete, static text document, while captions are synchronized text displayed within video content.
UA	User agent, any software that retrieves, renders, and facilitates user interaction with web content, such as browsers, screen readers, or mobile applications.
UI	User Interface
VPAT	Voluntary Product Accessibility Template, a document that helps organizations assess the accessibility of their products and services. It is a standardized template used to report how well a product conforms to accessibility standards, such as Section 508 and WCAG. Essentially, it is a way for vendors to document and communicate the accessibility features of their offerings.
WCAG	Web Content Accessibility Guidelines represent a single shared standard for web content accessibility that meets the needs of individuals, organizations, and governments internationally. Web “content” generally refers to the information in a web page or web application, including: natural information such as text, images, and sounds code or markup that defines structure, presentation, etc.
White space characters	Invisible characters used for spacing and formatting in text that don't display visible marks on screen or paper. Examples: Space Tab Line break Carriage return