Accessibility Glossary: 200 Web Accessibility Terms Explained In Plain English

Clear definitions of the WCAG, ARIA, ADA, Section 508 and European Accessibility Act terms you will meet in audits, VPATs and legal letters. Reviewed by our founder, an IAAP CPACC, WAS and CPWA certified specialist with 10+ years of hands-on accessibility testing.

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Turn These Terms Into A Plan

Looked up a term? These guides answer the questions people ask next. New here and not sure what you need? Book a free 30-minute call: a first conversation to understand where you stand and scope your project. Already have scan results or audit findings to go through with your developer? The $100 one-hour technical consultation is built for that.

What Does An Audit Cost?

What drives the price of an accessibility audit, what each package includes and how to compare quotes before you buy.

Read the audit cost guide

Got An ADA Demand Letter?

What to do in the first days after a demand letter or lawsuit, and how an audit and documented fixes support your response.

Read the ADA lawsuit guide

How Remediation Works

How audit findings become code, content and design fixes, and how each fix is retested so you can show it is resolved.

Read the remediation guide

Automated Scans Vs Manual Testing

What automated accessibility testing catches, where it stops, and why a manual review with a screen reader still matters.

Read the testing guide

Selling In The EU?

What the European Accessibility Act requires, who it covers and how EN 301 549 and WCAG fit together.

Read the EAA guide

Do Overlays Make A Site Compliant?

Why accessibility widgets do not fix the underlying code, and what courts and the FTC have said about them.

Read the overlays guide

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From Definition To Fix

Accessibility Glossary Terms Buyers Ask About Most

This accessibility glossary explains 200 terms in plain English. If you are buying an audit or answering a procurement request, start with accessibility audit, WCAG, success criterion, conformance level, VPAT, ACR, accessibility remediation, tagged PDF and accessibility roadmap. For the laws behind them, see ADA Title II, ADA Title III, Section 508, the European Accessibility Act and EN 301 549. Technical definitions follow the W3C’s WCAG 2.2 text.

Accessibility Audit

A structured review of your site against WCAG 2.2 Level AA using screen readers, the keyboard and automated scans. Our Quick Audit is $500 and a complete audit is $2,000.

Accessibility Audit Services

VPAT And ACR

A VPAT is the ITI reporting template. Once it is filled in from real testing it becomes an Accessibility Conformance Report (ACR), which buyers and Section 508 reviewers ask for.

VPAT And ACR Documentation

Accessibility Remediation

Fixing the issues an audit finds in your code, content or CMS settings, then retesting each fix so you can show it is resolved.

Accessibility Remediation

ADA Demand Letter

A letter claiming your website breaks the ADA, often sent before a lawsuit. An expert audit and documented fixes are the usual first response.

ADA Lawsuit Remediation

Tagged PDF

A PDF with a tag tree that gives screen readers its headings, reading order, tables and alt text. PDF/UA (ISO 14289) is the standard for accessible PDFs.

Document Accessibility Testing

Accessibility Roadmap

A prioritised plan for fixing issues and keeping them fixed, with owners, dates and scheduled retests after each release.

Accessibility Monitoring

All Accessibility Glossary Terms From A To Z

200 definitions covering WCAG success criteria, ARIA, assistive technology, testing tools and accessibility laws around the world. Select a term to read the full definition.

Color Vision Deficiency (Color Blindness)

Color vision deficiency, commonly called color blindness, is a reduced ability to distinguish between certain colors, most often red and green, affecting a significant share of men in particular.

Combobox Pattern

The WAI-ARIA design pattern for an editable text input paired with a list of filtered suggestions, such as an autocomplete search field or a searchable select menu.

Conformance Level (A, AA, AAA)

WCAG conformance levels (A, AA, and AAA) rank how strictly a site meets the guidelines, with A as the minimum, AA as the standard most laws and organizations target, and AAA as the highest, most demanding level.

Consistent Help

A WCAG 2.2 success criterion (3.2.6, Level A) requiring that help mechanisms, like a contact link, chat widget, or FAQ link, appear in the same relative order on every page where they exist.

Consistent Identification

A WCAG success criterion (3.2.4, Level AA) requiring that components with the same function be identified consistently across a site, using the same label, icon, or name.

Consistent Navigation

A WCAG success criterion (3.2.3, Level AA) requiring that navigation mechanisms repeated across multiple pages appear in the same relative order each time.

Content on Hover or Focus

A WCAG 2.1 success criterion (1.4.13, Level AA) governing tooltips and other content that appears on mouse hover or keyboard focus, requiring it to be dismissible, hoverable, and persistent.

Continuous Accessibility

An operating model where accessibility is maintained as an ongoing, continuous practice through monitoring, testing, and process integration, rather than a one-time audit and fix project.

Continuous Integration Accessibility Testing

Running automated accessibility scans as part of an automated build and deployment pipeline, so new code is checked for regressions before it reaches production.

Dark Mode

A display setting that inverts a typical light interface to a dark background with light text, reducing screen brightness and glare for many users.

DDA (Disability Discrimination Act, Australia)

The Disability Discrimination Act 1992 (DDA) is Australia's federal law prohibiting disability discrimination, and it's the primary legal basis for web accessibility obligations for both government and business websites.

Deaf and Hard of Hearing

Deaf and hard of hearing describes a spectrum of hearing loss, from partial to total, and the primary digital accessibility need for this group is text or visual alternatives to audio content.

Design System Accessibility

Design system accessibility means building accessibility directly into a reusable component library (buttons, forms, modals, and so on) once, so every product team using the design system inherits accessible components by default.

Digital Accessibility

Digital accessibility is the practice of designing and building websites, apps, and digital documents so that people with disabilities can perceive, navigate, and interact with them as effectively as everyone else.

Digital Accessibility Budget

The dedicated funding an organization allocates for accessibility work, spanning audits, remediation, training, tooling, and ongoing monitoring, rather than treating it as an unfunded ad hoc expense.

Digital Accessibility Policy

A digital accessibility policy is an organization's internal, written commitment to accessibility: the standard it follows, who is responsible for it, and how it gets checked before content and features ship.

Digital Accessibility Risk Assessment

A digital accessibility risk assessment evaluates an organization's exposure to accessibility-related legal, financial, and reputational risk, typically combining a technical review of its digital properties with a look at its industry, jurisdiction, and past complaint history.

Put The Terms To Work

Not Sure Which Of These Terms Apply To Your Site?

New here? Start with a free 30-minute call to understand where you stand and scope your project. Already have scan results or audit findings to work through with your developer? Book the $100 one-hour technical consultation. Ready for findings? Start with a $500 Quick Audit or a $2,000 complete audit.

Frequently Asked Questions

What is an accessibility glossary?

An accessibility glossary is a list of the terms used in digital accessibility, from standards such as WCAG and EN 301 549 to laws, assistive technologies and testing methods, each explained in plain language. Ours has 200 terms, written and reviewed by the web accessibility experts who run our audits.

What is the difference between WCAG, the ADA and Section 508?

WCAG is the W3C’s technical standard for accessible web content. The ADA is a US civil rights law: the Department of Justice’s Title II web rule requires state and local governments to meet WCAG 2.1 Level AA by April 26, 2027 (populations of 50,000 or more) or April 26, 2028 (smaller entities and special districts). Section 508 covers US federal agencies, and its standards incorporate WCAG 2.0 Level AA. See ADA Title II, ADA Title III and Section 508 in the glossary.

What is the difference between a VPAT and an ACR?

A VPAT (Voluntary Product Accessibility Template) is the blank reporting template published by the Information Technology Industry Council. When it is completed from real testing, the result is an Accessibility Conformance Report (ACR). We write ACRs from hands-on testing through our VPAT and ACR documentation service.

What does WCAG 2.2 Level AA mean?

WCAG 2.2 became a W3C Recommendation on 5 October 2023. It adds nine success criteria to WCAG 2.1, such as Target Size (Minimum) and Accessible Authentication, and removes 4.1.1 Parsing (W3C: What’s New in WCAG 2.2). Level AA means a page meets every Level A and Level AA success criterion. It is the level most laws and contracts ask for.

How much does an accessibility audit cost?

Our packages are fixed prices: a one-hour technical consultation (audit walkthrough, developer Q&A or live issue review) is $100, a Quick Accessibility Audit is $500, and a complete audit is $2,000, including the Shopify Accessibility Audit. Remediation and VPATs are quoted after we see the findings. See accessibility audit pricing for what each package includes.

Can an automated scanner or overlay make my website compliant?

No. Automated tools cannot check every WCAG requirement, which is why the W3C’s guidance on evaluation tools says to combine them with manual review. An accessibility overlay does not fix the underlying code either; read why in accessibility overlays and ADA lawsuits. Our audits pair scans with manual testing in NVDA, JAWS, VoiceOver and the keyboard.

Who writes and reviews these glossary definitions?

Our web accessibility experts. Reviews are led by founder Mohammad Shadab Saifi, who has 10+ years in digital accessibility and holds the IAAP CPACC, WAS and CPWA certifications. If a term on your audit report is unclear, book a $100 consultation and we will walk you through it.

I am new to accessibility. Where should I start?

Read WCAG and accessibility audit first, then the guide that fits your situation: audit cost, an ADA demand letter or the European Accessibility Act. When you want to talk it through, book a free 30-minute call. It is a first conversation to understand where you stand and scope a project. If you already have scan results or audit findings to go through with your developer, the $100 one-hour technical consultation is the better fit.