Accessibility Glossary

Plain-English definitions of 75+ digital accessibility terms covering WCAG 2.2, assistive technologies, disability groups, design and code, compliance and audit process. Every entry cross-references the tools, services and WCAG success criteria you can act on next.

Quick answer

What is the ExceedAbility Accessibility Glossary?

This glossary defines 75 digital accessibility terms in plain English, grouped across six categories: WCAG and standards, assistive technology, disability, design and code, compliance and legal, and process and delivery. Every term links to the relevant ExceedAbility tool, service or WCAG success criterion, so you can move from definition to action in one click. Use the WCAG Criteria Search for rule-level detail, the tools page for self-service resources, or contact our team to discuss applying any of these to your product. Free, no signup, maintained by an Australian accessibility delivery partner.

Last reviewed: May 2026

Showing all 75 terms.

Accessibility audit

Process & delivery

A structured assessment of a digital product against WCAG or another accessibility standard. ExceedAbility audits combine automated scanning, expert manual review and assistive-technology testing, and produce findings with severity ratings, evidence and prioritised remediation guidance.

Standardised document reporting how a product or service conforms to specific accessibility standards (WCAG, EN 301 549, Section 508). The VPAT is the most widely used ACR format and is routinely requested in government procurement.

Accessibility statement

Compliance & legal

A public document declaring an organisation's accessibility commitments, current conformance level, known limitations and how to report problems. Required by the Australian Digital Service Standard for public-facing government services.

Accessibility supported

WCAG & standards

WCAG terminology meaning a technique actually works with the assistive technology users have, not just that it is theoretically conformant. Custom widgets must be tested across the major screen readers, not assumed compliant from ARIA markup alone.

Accessibility tree

Design & code

The browser's internal representation of a page that is exposed to assistive technology. Built from the DOM plus ARIA, then consumed by screen readers and other AT. What you see in the accessibility tree is what AT users get.

United States civil rights law prohibiting discrimination on the basis of disability. Title III is increasingly applied to websites and digital services, with WCAG 2.1 AA the de facto benchmark cited in settlement agreements.

ADHD user

Disability

Attention deficit hyperactivity disorder. Users typically benefit from reduced distractions, manageable content chunks, the ability to pause animations or auto-play media, and clear focus states that help maintain attention on the current task.

ARIA

Design & code

Accessible Rich Internet Applications. W3C specification of attributes that expose accessible semantics to assistive technology where native HTML cannot. The first rule of ARIA is: do not use ARIA if a semantic HTML element will do.

aria-describedby

Design & code

ARIA attribute pointing to another element that provides supplementary description for the current element, such as a form field's help text or error message. Read by screen readers after the element's accessible name.

aria-label

Design & code

ARIA attribute that supplies an accessible name for an element when visible text is missing or insufficient, such as an icon-only button. Overrides visible text for screen readers, so use carefully when text is also present.

W3C guidelines for content management systems and authoring tools, in two parts: the tool itself is accessible to authors with disabilities, and the tool helps authors produce accessible content by default.

Auditory disability

Disability

Reduced or absent ability to hear. Includes Deaf users (no functional hearing) and hard-of-hearing users (reduced hearing). Requires captions, transcripts, sign-language interpretation where appropriate, and visual alternatives to audio cues.

Autistic user

Disability

A user on the autism spectrum. Typically benefits from predictable layouts, consistent navigation, literal language, and reduced sensory overload from animation, sound, busy backgrounds or unexpected interactions.

Automated accessibility testing

Process & delivery

Software-based scanning for accessibility issues using tools such as axe, WAVE, Lighthouse and Pa11y. Catches roughly 30-40 percent of WCAG failures; the remainder require manual review and assistive-technology testing.

Blind user

Disability

A person with little to no functional vision. Typically uses a screen reader to navigate digital content via keyboard, relying entirely on semantic structure: headings, landmarks, accessible names and alt text.

Braille display

Assistive technology

Hardware device with pins that rise and fall to render text in refreshable braille, paired with a screen reader. Used by deaf-blind users and many blind users who prefer tactile reading or work in quiet environments.

Captions

Assistive technology

Synchronised text alternatives for audio in video, including dialogue and relevant non-speech audio. Required for pre-recorded video with audio at WCAG 1.2.2 (Level A) and for live audio at WCAG 1.2.4 (Level AA).

Differences in how a person processes information, including memory, attention, language and executive function. Users benefit from plain language, predictable layouts, generous time limits and the ability to pause animations.

Colour blindness

Disability

Inability or reduced ability to distinguish certain colours, most commonly red-green. Affects roughly 8 percent of men and 0.5 percent of women. Information must never depend on colour alone (WCAG 1.4.1).

Colour contrast

Design & code

The measurable ratio of luminance between foreground and background. WCAG 2.2 AA requires 4.5:1 for normal text and 3:1 for large text and UI components. Common failure point in brand-driven design systems.

Conformance

WCAG & standards

Meeting all WCAG success criteria at the chosen level. Conformance applies to a complete web page, not a fragment, and to a defined scope of pages or screens within a product.

WCAG's three levels of strictness. Level A is the floor (no critical barriers). Level AA is the de facto standard required by most legislation including the Australian Digital Service Standard. Level AAA is aspirational; not all content can practically meet it.

Australian Commonwealth law making it unlawful to discriminate against a person on the basis of disability. Inaccessible digital services can lead to formal complaints to the Australian Human Rights Commission.

Deaf user

Disability

A person who cannot access audio at all. Needs accurate synchronised captions, transcripts, sign-language interpretation where appropriate, and visual equivalents for any audio cue or alert.

Digital Service Standard (DSS)

Compliance & legal

Australian Government framework requiring digital services to meet accessibility, design and operational quality criteria. Accessibility is required at WCAG 2.2 Level AA for new services from 1 January 2025 and existing services from 1 January 2026.

Disability

Disability

The interaction between a person's impairment and barriers in their environment. The W3C identifies five primary functional disability groups affecting digital accessibility: visual, auditory, cognitive, physical and speech.

Australian Commonwealth body responsible for digital service standards across government, including accessibility reporting through the Investment Oversight Framework and the Digital Service Standard.

Dyslexic user

Disability

A user with dyslexia, a specific learning difference affecting reading. Benefits from readable typefaces, generous line and letter spacing, plain language, optional text-to-speech, tolerant search, and forms that forgive misspellings.

EN 301 549

Compliance & legal

European Union standard for ICT accessibility, mandatory for public-sector digital services across EU member states. Builds on WCAG 2.1 and adds requirements for hardware, software and documentation.

European Accessibility Act

Compliance & legal

EU directive (in force from June 2025) requiring private-sector products and services to be accessible, including banking, e-commerce, ebooks, transport and consumer electronics. Increasingly influencing global product accessibility design.

Eye tracking

Assistive technology

Assistive input method that uses eye position to control a cursor and trigger selections. Used by people with severe motor impairments such as ALS. Requires generous target sizes and dwell-based activation patterns.

Focus order

Design & code

The sequence in which keyboard focus moves through interactive elements as the user presses Tab. Must follow a logical, predictable order matching visual reading order (WCAG 2.4.3).

Visible outline or change in appearance showing which element currently has keyboard focus. Required for all interactive elements (WCAG 2.4.7). Removing default focus styles without replacement is a critical accessibility failure.

A user with reduced but not absent hearing. Benefits from adjustable audio levels, separate dialogue and background tracks, accurate captions, low background noise, and clear well-paced speech in spoken content.

Heading structure

Design & code

Hierarchical use of HTML headings (h1 through h6) to convey document outline. Screen reader users navigate by heading; broken hierarchy or skipped levels makes content harder to scan and orient within.

Inclusive design

Process & delivery

Design philosophy treating disability and difference as central rather than as edge cases. Produces solutions for the widest range of users, and incidentally better outcomes for everyone (the curb-cut effect).

Australian Government framework requiring agencies to report on digital service accessibility. Non-compliance can trigger investment-board attention and procurement consequences for suppliers delivering inaccessible work.

JAWS

Assistive technology

Job Access With Speech. The most widely used commercial screen reader on Windows, made by Freedom Scientific. A reference target for screen reader testing alongside NVDA and VoiceOver.

Keyboard accessibility

Design & code

Every interactive element must be reachable and operable using a keyboard alone, with no traps and a visible focus indicator (WCAG 2.1.1, 2.1.2, 2.4.7). Foundational for keyboard, switch and voice-control users.

Landmarks

Design & code

HTML5 sectioning elements (header, nav, main, aside, footer) and equivalent ARIA roles that allow screen reader users to jump between major page regions. Should appear once per page (except navigation) and be labelled when repeated.

Live regions

Design & code

ARIA mechanism (aria-live, role="status", role="alert") that notifies screen reader users of content changes without moving focus. Used for form validation, toast messages, search results updating and notifications.

Low vision user

Disability

A person with visual impairment that cannot be corrected to normal vision. Uses zoom up to 400 percent, magnification or high-contrast modes; needs layouts that reflow without horizontal scrolling at small viewports.

Manual accessibility testing

Process & delivery

Human review of digital content against accessibility criteria, including keyboard-only navigation, screen reader testing and visual inspection. Catches WCAG failures that automated tools cannot detect, particularly around meaning, context and assistive-technology support.

A user with reduced control of movement, including tremor, paralysis, weakness or chronic pain. May interact via keyboard, switch, voice control or eye tracking, and needs large well-spaced targets and forgiving inputs.

Narrator

Assistive technology

Microsoft's built-in screen reader for Windows. Free and ships with the operating system. Less feature-rich than JAWS or NVDA but useful for quick accessibility checks without installing additional software.

NVDA

Assistive technology

NonVisual Desktop Access. Free, open-source screen reader for Windows produced by NV Access (Australian-founded). Used by approximately half of Windows screen reader users globally and a primary testing target for web accessibility.

PDF/UA

Compliance & legal

PDF Universal Accessibility (ISO 14289-1). The accessibility standard for PDF documents, requiring tagged content, defined reading order, language metadata, accessible forms and proper structure for assistive technologies.

Seizures triggered by flashing or rapidly changing visual content. WCAG 2.3.1 prohibits content that flashes more than three times per second above defined luminance and red-flash thresholds.

Plain language

Design & code

Writing designed to be understood at first reading by the intended audience. WCAG 3.1.5 (Level AAA) recommends plain language. Australian Government style guidance targets a Year-9 reading level for general public content.

Reading order

Design & code

The sequence in which content is read by assistive technology, determined by the DOM order. Must match visual reading order; CSS positioning that visually reorders content but not the DOM creates a mismatch and an accessibility failure.

Refreshable braille

Assistive technology

Output mode of a braille display in which mechanical pins rise and fall to represent the current line of text. Updates in real time as the screen reader cursor moves through content.

Remediation

Process & delivery

Fixing accessibility issues identified by an audit. May apply to websites, applications, documents (PDF, Word, PowerPoint) or multimedia. ExceedAbility document remediation includes tagged source files and PDF/UA-compliant outputs.

Screen magnifier

Assistive technology

Software that enlarges part of the screen for low-vision users. Examples include ZoomText, Windows Magnifier and macOS Zoom. Effective only when layouts reflow at the magnification level rather than triggering horizontal scroll.

Screen reader

Assistive technology

Software that converts on-screen content into synthesised speech or refreshable braille. Used primarily by blind and many low-vision users. Major examples: JAWS and NVDA on Windows, VoiceOver on macOS and iOS, TalkBack on Android, Narrator on Windows.

Section 508

Compliance & legal

United States federal law requiring electronic information technology used by federal agencies to be accessible. Currently aligned with WCAG 2.0 Level AA via the Section 508 Refresh and increasingly invoked in procurement worldwide.

Semantic HTML

Design & code

Use of HTML elements according to their meaning (button for buttons, nav for navigation, h2 for headings) rather than styled divs. Provides accessibility for free via the browser's accessibility tree and is the foundation that ARIA builds on.

A user with difficulty producing intelligible speech, ranging from articulation differences to non-speaking. Needs text-based alternatives to voice interfaces, IVR menus and speech authentication, plus support for augmentative communication devices.

Success criterion

WCAG & standards

A specific, testable WCAG rule. WCAG 2.2 contains 87 success criteria across Level A, AA and AAA, organised under the four POUR principles. Each criterion has techniques showing how to meet it and failures showing how it commonly breaks.

Switch device

Assistive technology

Single-button or multi-button input device used by people with severe motor impairments. Combined with scanning interfaces in the operating system or assistive software to operate computers without a keyboard or mouse.

TalkBack

Assistive technology

Google's built-in screen reader for Android. Free and ships with the operating system. Used by blind and low-vision users to operate phones and tablets via touch gestures and synthesised speech.

Target size

Design & code

The interactive area of a control such as a button or link. WCAG 2.5.8 (Level AA, new in 2.2) requires touch targets of at least 24 by 24 CSS pixels with adequate spacing; WCAG 2.5.5 (Level AAA) prefers 44 by 44.

A user with an inner-ear condition causing motion sensitivity. Affected by parallax effects, large slide transitions and auto-scrolling. WCAG 2.3.3 (Level AAA) and the prefers-reduced-motion media query address these patterns.

Voice control

Assistive technology

Software that allows hands-free operation of a device by speech, such as Dragon NaturallySpeaking, macOS Voice Control and Windows Voice Access. Used by people with motor disabilities and increasingly by general users for convenience.

VoiceOver

Assistive technology

Apple's built-in screen reader on macOS, iOS and iPadOS. Operated via gestures on touch devices and keyboard or trackpad shortcuts on Mac. The reference target for testing accessibility on Apple platforms.

A widely-used form of Accessibility Conformance Report originating in the US, documenting how a product conforms to WCAG, Section 508 or EN 301 549. Required in many US, EU and Australian government procurements.

WAI-ARIA

WCAG & standards

Web Accessibility Initiative - Accessible Rich Internet Applications. The full name of the ARIA specification published by the W3C Web Accessibility Initiative.

The W3C standard for digital accessibility, used worldwide as the basis for accessibility law and policy. Organised around four principles (POUR) and three conformance levels (A, AA, AAA).

WCAG 2.2

WCAG & standards

Current published version of WCAG (October 2023). Adds nine new success criteria over WCAG 2.1, focused mainly on motor disabilities and cognitive accessibility. Required for new Australian government services from 1 January 2025.

ZoomText

Assistive technology

Screen magnification and reading software for Windows, made by Freedom Scientific. Combines magnification, contrast enhancement and text-to-speech for low-vision users in a single product.

Common questions about accessibility terminology

Plain answers to the questions buyers, designers, developers and content authors ask most often.

What is digital accessibility?

Digital accessibility is the practice of designing and building websites, applications and documents so that people with disabilities can use them. It addresses barriers across five functional disability groups (visual, auditory, cognitive, physical and speech) and is most often measured against the W3C Web Content Accessibility Guidelines (WCAG).

What is the difference between WCAG 2.1 and WCAG 2.2?

WCAG 2.2 (October 2023) adds nine new success criteria to WCAG 2.1, focused mainly on motor disabilities and cognitive accessibility. Notable additions at Level AA include 2.4.11 Focus Not Obscured, 2.5.7 Dragging Movements, 2.5.8 Target Size (Minimum) and 3.3.7 Redundant Entry. WCAG 2.2 is required for new Australian government digital services from 1 January 2025.

What WCAG conformance level should I aim for?

Level AA is the de facto standard required by most accessibility legislation, including the Australian Digital Service Standard, the EU Web Accessibility Directive and Section 508. Level A is the floor (no critical barriers) and Level AAA is aspirational; not all content can practically meet AAA. Most engagements target Level AA across all in-scope pages.

What is the difference between an accessibility audit and a VPAT?

An accessibility audit is the assessment process: testing against WCAG and producing findings with severity ratings and remediation guidance. A VPAT (Voluntary Product Accessibility Template) is one format of Accessibility Conformance Report, a public-facing summary of how a product conforms to WCAG, Section 508 or EN 301 549. An audit typically informs a VPAT but is much more detailed.

Which screen reader should I test with?

Test with the screen readers your users actually use. For most public-facing Australian services that means NVDA and JAWS on Windows, VoiceOver on macOS and iOS, and TalkBack on Android. WebAIM's annual Screen Reader User Survey reports JAWS, NVDA and VoiceOver collectively cover roughly 95 percent of screen reader users globally.

How do I make a PDF accessible?

Accessible PDFs require: proper document tags (headings, lists, paragraphs, tables), defined reading order, alt text on informative images, accessible form fields, language metadata, and a document title set in document properties. PDF/UA (ISO 14289-1) is the formal standard. ExceedAbility's document remediation service delivers tagged source files and PDF/UA-compliant outputs.

Need this applied to your product?

Contact our team to scope an audit, document remediation pass, or capability uplift programme. A 20-minute Discovery Call is usually enough to scope the work.

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