Glossary of Terms
This page contains a list of terms that might not be immediately obvious to readers so there is a more detailed explanation for each in the list below.
- accessibility tree
- a subset of the DOM (Document Object Model) tree containing elements exposed to assistive technologies. Only elements that can have, for instance, accessible name, role, and value are included there. As an example, the
<div>element without defined role is not present in the accessibility tree. - accessible name
- a programmatically determined name of a user interface element that is included in the accessibility tree. The accessible name of the
<button>element, for example, can be determined from the text content inside,aria-labelattribute, oraria-labelledbyattribute reference. - audio descriptions
- an audio track that narrates the relevant visual information contained in a video, such as actions, characters, scene changes, or on-screen text.
- braille display
- a screen-reader-controlled device for physical displaying braille characters in a form of pins raised through holes in a flat surface.
- CAPTCHA
- a test designed to differentiate a human from a computer - initialism for "Completely Automated Public Turing test to tell Computers and Humans Apart".
- conformance
- meeting or satisfying the requirements of the standard. In WCAG the requirements are the Success Criteria. To conform to WCAG, you need to satisfy the Success Criteria, that is, there is no content which violates the Success Criteria.
- landmark region
- landmark regions (or ARIA landmarks) are attributes used to define and label specific regions within a web page, such as the main content or navigation, by providing information to assistive technologies about the structure and purpose of these regions.
- media alternative
- audio-only, video-only (including sign-language video), or audio-video media that presents no more information than is already presented in text.
- non-text content
- any content that is not a sequence of characters - for instance, images, charts, graphs, or audio/video content.
- programmatically determined
- marked up content having semantic structure and relationships that allows various technologies to programmatically retrieve it and present it to users in different ways. For instance, putting text into the
<h1>element allows the browser to create the page heading outline, CSS to apply different styles to it, and screen readers to announce the element as "heading level one". - screen reader
- an assistive technology software that renders text and image content as speech or braille output.
- synchronized media
- audio or video content synchronized with another format for presenting information, such as video + audio, video + captions, or video + audio descriptions
- transcript
- a text version of audio content; it must have identified speakers (if there is more than one) and must cover all dialogues and important sound effects. It may also contain timestamps when necessary.