Non-text Contrast
A WCAG 2.1 success criterion (1.4.11, Level AA) requiring buttons, form field borders, icons, and other meaningful graphics to have a contrast ratio of at least 3:1 against their surrounding color.
Read moreGlossary Terms
On-Screen Keyboard
A software keyboard displayed on screen that users select with a mouse, touch, switch, or eye-tracking device instead of typing on a physical keyboard.
Read morePause, Stop, Hide
A WCAG success criterion (2.2.2, Level A) requiring that users be able to pause, stop, or hide any moving, blinking, scrolling, or auto-updating content that lasts more than five seconds.
Read morePDF Accessibility (Tagged PDF)
The practice of structuring a PDF with an underlying tag tree, reading order, and text alternatives so screen readers and other assistive technology can interpret it correctly.
Read morePerceivable
Perceivable is the first of WCAG's four principles: information and interface elements must be presented in ways every user can perceive, regardless of which senses they rely on.
Read morePlain Language
A writing approach using clear, direct sentences and familiar words so content is understandable by the widest possible audience, including people with cognitive disabilities and limited English proficiency.
Read morePointer Cancellation
A WCAG 2.1 success criterion (2.5.2, Level A) requiring that functions triggered by a single pointer be actioned on the up-event, not the down-event, so a user can move away to cancel.
Read morePointer Gestures
A WCAG 2.1 success criterion (2.5.1, Level A) requiring that any function operated by a multipoint or path-based gesture, like pinch-to-zoom or swipe, also be operable with a single-pointer action.
Read morePOUR Principles
POUR is the acronym for the four core principles WCAG is organized around: content must be Perceivable, Operable, Understandable, and Robust.
Read moreProcurement Accessibility Requirements
Procurement accessibility requirements are accessibility conditions a buyer, often a government agency, university, or large enterprise, builds into its purchasing process, requiring vendors to demonstrate conformance before a contract is awarded.
Read moreProgressive Enhancement
A development approach that builds a fully functional, accessible baseline experience first, then layers on enhanced styling and interactivity for browsers and devices that support it.
Read morePSBAR (Public Sector Bodies Accessibility Regulations, UK)
UK regulations requiring public sector websites and mobile apps to meet WCAG 2.2 Level AA and publish a detailed accessibility statement.
Read moreReadability Score
A calculated metric, such as the Flesch-Kincaid grade level, that estimates how difficult a piece of text is to read based on sentence length and word complexity.
Read moreReasonable Accommodation
A reasonable accommodation is a change to a policy, practice, or environment that lets a person with a disability participate, without imposing an undue hardship on the organization providing it.
Read moreReduced Motion (OS Setting)
An operating system setting that signals a user's preference for minimal animation, which websites can detect and honor through the prefers-reduced-motion CSS media feature.
Read moreRedundant Entry
A WCAG 2.2 success criterion (3.3.7, Level A) requiring that information a user already provided earlier in a process not be required again, unless it is essential or a security concern.
Read moreRefreshable Braille Notetaker
A portable assistive device with a row of mechanical pins that raise and lower to form braille characters, letting blind users read digital text by touch and often take notes.
Read moreRegression Testing (Accessibility)
Accessibility regression testing means re-checking previously fixed issues and unrelated pages after a code change, to catch cases where a new feature or update accidentally reintroduces an old barrier or creates a new one.
Read moreRehabilitation Act Section 501
A provision of the US Rehabilitation Act requiring federal agencies to practice affirmative action and nondiscrimination in employment for people with disabilities, distinct from Section 508's technology-access rules.
Read moreResize Text
A WCAG success criterion (1.4.4, Level AA) requiring text to remain readable and functional when resized up to 200 percent without assistive technology, without loss of content or function.
Read moreRGAA (France)
France's Référentiel Général d'Amélioration de l'Accessibilité, the official technical framework used to audit and certify the accessibility of French public and increasingly private digital services.
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