Glossary: terms in brief.

A public statement of how accessible a website or app is, which parts are not yet accessible and how to report a barrier. Public sector bodies in the EU must publish one. Our statement generator helps you draft it.

The name assistive technology announces for a control, such as “Search” for a magnifying-glass button. It comes from visible text, a label or ARIA attributes, and should contain the visible label text.

Criteria: 4.1.2 Name, Role, Value, 2.5.3 Label in Name, 1.1.1 Non-text Content

A short text that stands in for an image for people who cannot see it. It conveys the image’s content and purpose; purely decorative images get empty alt text.

Criteria: 1.1.1 Non-text Content

Accessible Rich Internet Applications: a W3C specification of attributes such as role, aria-label and aria-expanded that tell assistive technology the role, name and state of custom controls. Rule of thumb: if a native HTML element does the job, use it instead.

Criteria: 4.1.2 Name, Role, Value, 1.3.1 Info and Relationships

Narration, fitted into natural pauses, of what happens on screen that matters for understanding. Required for prerecorded video at Level AA. See our video guide.

Criteria: 1.2.3 Audio Description or Media Alternative (Prerecorded), 1.2.5 Audio Description (Prerecorded)

An open-source library of automated accessibility rules that runs in the browser. It finds many issues but not all; our scanner uses it as one building block among several.

Germany’s Barrierefreiheitsstärkungsgesetz, the national law that transposes the European Accessibility Act. It has applied since 28 June 2025.

Germany’s regulation on accessible information technology for federal public bodies. It refers to the harmonised standard EN 301 549 and requires, among other things, an accessibility statement.

Text for the soundtrack of a video, written for people who cannot hear it: dialogue plus speaker names and meaningful sounds. Subtitles that only translate dialogue are not the same thing. Required for prerecorded and live video.

Criteria: 1.2.2 Captions (Prerecorded), 1.2.4 Captions (Live)

WCAG assigns each success criterion a level: A is the baseline, AA the usual target in laws and standards, AAA the highest. Conforming at AA means meeting every A and AA criterion; in WCAG 2.2 that is 55.

The difference in luminance between foreground and background, from 1:1 to 21:1. Level AA requires at least 4.5:1 for normal text, 3:1 for large text and 3:1 for UI components and graphics. Try our contrast checker.

Criteria: 1.4.3 Contrast (Minimum), 1.4.11 Non-text Contrast

Directive (EU) 2019/882 on accessibility requirements for products and services. Member States have applied it since 28 June 2025 through national laws.

A strongly simplified form of language with fixed rules: very short sentences, one idea per sentence, explained words, often supported by pictures. It is mainly for people with learning disabilities, and texts are ideally checked by them. In German it is called Leichte Sprache.

The European standard for the accessibility of ICT products and services. For web content, version 3.2.1 refers to WCAG 2.1 Level AA; other clauses cover software, documents and hardware.

The element that currently receives keyboard input, such as a link or a form field. Focus must be visible and must not be entirely hidden by other content.

Criteria: 2.4.7 Focus Visible, 2.4.11 Focus Not Obscured (Minimum)

The order in which the Tab key moves through interactive elements. It must preserve meaning and make sense for operating the page.

Criteria: 2.4.3 Focus Order

A part of the page you can tab into but not out of, often an embedded player or a dialog. WCAG does not allow keyboard traps.

Criteria: 2.1.2 No Keyboard Trap

A marked-up page region such as header, navigation, main content or footer (header, nav, main, footer in HTML). Screen reader users use landmarks to jump straight to a region.

Criteria: 1.3.1 Info and Relationships, 2.4.1 Bypass Blocks

A part of the page whose changes a screen reader announces automatically, without moving focus, such as “3 results found”. It is marked with aria-live or roles such as status and alert.

Criteria: 4.1.3 Status Messages

A third-party script that tries to alter a website in the browser or adds an accessibility toolbar. It does not change the source code and does not make a site conformant. See our overlay guide.

ISO 14289, the standard for accessible PDF files (Universal Accessibility). It defines how tags, reading order, language and metadata must be built. See our PDF guide.

Criteria: 1.3.1 Info and Relationships, 1.3.2 Meaningful Sequence

Clear everyday language with short sentences and little jargon, written for a broad audience. Unlike Easy Read it has no fixed rulebook and is not usually tested with a specific group of readers.

The order in which assistive technology reads content. It follows the code, or the tags in a PDF, rather than the visual layout, and must keep the meaning intact.

Criteria: 1.3.2 Meaningful Sequence

At a width of 320 CSS pixels, for example at 400% zoom, content must rearrange itself so that you do not have to scroll in two directions. Content that needs a two-dimensional layout, such as maps or large data tables, is exempt.

Criteria: 1.4.10 Reflow

Software that enlarges part of the screen, often with colour and contrast options. Users see only a small part of the page at a time, so messages far from the focus are easy to miss.

Criteria: 1.4.4 Resize Text, 1.4.10 Reflow, 1.4.13 Content on Hover or Focus

Software that reads screen content aloud or sends it to a braille display, operated by keyboard or gestures. Well-known examples are NVDA on Windows and VoiceOver on Apple devices.

Criteria: 1.1.1 Non-text Content, 1.3.1 Info and Relationships, 4.1.2 Name, Role, Value

Using HTML elements for what they mean: h1 to h6 for headings, button for buttons, ul for lists. Assistive technology then understands structure and roles without extra ARIA.

Criteria: 1.3.1 Info and Relationships, 4.1.2 Name, Role, Value

A link at the top of the page, often visible only on focus, that jumps straight to the main content, so keyboard users do not have to tab through the whole navigation on every page.

Criteria: 2.4.1 Bypass Blocks

The area you have to hit to click or tap a control. Level AA requires at least 24 × 24 CSS pixels, or enough spacing from neighbouring targets; there are exceptions, for example for links within a sentence.

Criteria: 2.5.8 Target Size (Minimum)

A sequence of steps to reach a goal, such as from product page to basket to completed order. We test selected journeys end to end, including with a screen reader, because one blocked step breaks the whole journey.

Criteria: 3.2.6 Consistent Help, 3.3.7 Redundant Entry, 3.3.8 Accessible Authentication (Minimum)

Software that lets people operate a computer by speech, for example “click Submit”. For this to work, a control’s accessible name must contain its visible label.

Criteria: 2.5.3 Label in Name

The W3C Web Content Accessibility Guidelines, the international reference standard for accessible web content. Version 2.2 has 55 success criteria at Levels A and AA, grouped under four principles: perceivable, operable, understandable, robust. See all criteria.