Reference
Accessibility Glossary
Plain-language definitions of the terms Shopify merchants encounter when working on accessibility compliance. Every term is linked to the canonical W3C / DOJ / EU primary source.
Alt text (alternative text)
Alt text is a written description of an image that screen readers announce to people who cannot see the image, and that search engines use to understand image content.
WCAG (Web Content Accessibility Guidelines)
WCAG is the international standard for web accessibility, published by the W3C, organized into 50+ testable success criteria across four principles: perceivable, operable, understandable, and robust.
Screen reader
A screen reader is assistive software that converts on-screen content into synthesized speech or refreshable braille, enabling blind and low-vision users to navigate websites, apps, and documents.
ARIA (Accessible Rich Internet Applications)
ARIA is a W3C specification of HTML attributes (`role`, `aria-label`, `aria-expanded`, etc.) that describe the structure and state of UI components for assistive technology.
ADA (Americans with Disabilities Act)
The ADA is the 1990 US federal civil-rights law that prohibits discrimination on the basis of disability; Title III applies to public accommodations including ecommerce websites.
EAA (European Accessibility Act)
The EAA (Directive 2019/882) is the European Union accessibility law requiring ecommerce services sold to EU consumers to meet WCAG 2.1 + 2.2 AA; enforcement began 28 June 2025.
Accessibility overlay
An accessibility overlay is a JavaScript widget that injects accessibility "fixes" at runtime without modifying source code; the DOJ and disability advocates do not consider overlays sufficient for ADA compliance.
Accessibility statement
An accessibility statement is a public-facing page declaring a website's conformance with accessibility standards, known limitations, and a contact mechanism for users to report issues.
Color contrast
Color contrast is the luminance ratio between text and its background; WCAG 2.1 AA requires at least 4.5:1 for body text and 3:1 for large text.
Keyboard navigation
Keyboard navigation is the ability to operate every interactive part of a website using only the keyboard — Tab, Shift+Tab, Enter, Space, Arrow keys, and Escape — without requiring a mouse.
Focus indicator
A focus indicator is the visible outline or styling that shows which element currently has keyboard focus, typically a 2-3px outline drawn by the browser.
Compliance score
A compliance score is the percentage of WCAG success criteria a website passes, typically calculated as `passed_criteria / total_criteria * 100`.
Section 508
Section 508 is the US federal law requiring electronic and information technology developed, procured, maintained, or used by federal agencies to be accessible to people with disabilities. The Section 508 standards were updated in 2017 to align with WCAG 2.0 AA.
VPAT (Voluntary Product Accessibility Template)
A VPAT is a standardized document, published by the Information Technology Industry Council (ITI), that vendors use to declare a product's conformance with Section 508 / WCAG accessibility standards.
ACR (Accessibility Conformance Report)
An Accessibility Conformance Report is a completed VPAT — the filled-in document that declares a specific product's actual conformance status against Section 508, WCAG, or EN 301 549 success criteria.
AODA (Accessibility for Ontarians with Disabilities Act)
AODA is the Ontario provincial law (Statutes of Ontario, 2005, Chapter 11) that mandates accessibility for organizations doing business in Ontario, with WCAG 2.0 AA as the technical standard for digital content.
EN 301 549
EN 301 549 is the harmonized European standard for accessibility requirements for ICT products and services, maintained by ETSI/CEN/CENELEC. The current version (V3.2.1, 2021) incorporates WCAG 2.1 Level AA as the web-content baseline; V4.x is in draft to incorporate WCAG 2.2.
RGAA (Référentiel Général d'Amélioration de l'Accessibilité)
The RGAA is France's national accessibility methodology, maintained by the Direction Interministérielle du Numérique (DINUM). The current version (RGAA 4.1) operationalizes WCAG 2.1 AA with 106 testable French-language criteria.
BFSG (Barrierefreiheitsstärkungsgesetz)
The BFSG is Germany's law transposing the European Accessibility Act (Directive 2019/882) into national law. It requires private-sector ecommerce, banking, e-books, and certain hardware to meet accessibility requirements aligned with EN 301 549. Effective date: 28 June 2025.
JAWS (Job Access With Speech)
JAWS is a Windows screen reader developed by Freedom Scientific (now Vispero). It is the most widely-used commercial screen reader in enterprise and government settings, with deep integration with Windows, Microsoft Office, and many third-party applications.
NVDA (NonVisual Desktop Access)
NVDA is a free, open-source Windows screen reader developed by NV Access. It is the most-used free screen reader and the second-most-used overall after JAWS.
VoiceOver
VoiceOver is Apple's built-in screen reader, shipping with macOS, iOS, iPadOS, watchOS, and tvOS. It is enabled via the keyboard shortcut Cmd+F5 on Mac or via Settings → Accessibility → VoiceOver on iOS.
ADA demand letter
An ADA demand letter is a pre-litigation notice from a plaintiff (often via a serial-plaintiff law firm) alleging that a website violates ADA Title III and demanding remediation plus a settlement payment, typically within 30-60 days.
Serial plaintiff
A serial plaintiff is an individual who files large numbers of ADA Title III lawsuits — typically through a small group of plaintiff law firms specializing in disability-rights litigation.
WAI-ARIA (Web Accessibility Initiative — Accessible Rich Internet Applications)
WAI-ARIA is the W3C Recommendation defining attributes (`role`, `aria-label`, `aria-expanded`, etc) that describe the structure and state of UI components for assistive technology. The current version is WAI-ARIA 1.2 (2023).
ADA Title III
ADA Title III is the section of the Americans with Disabilities Act (42 U.S.C. §§ 12181-12189) that prohibits discrimination on the basis of disability by private entities operating "places of public accommodation" — including, per US case law, commercial websites.
Rehabilitation Act (Section 504 + Section 508)
The Rehabilitation Act of 1973 prohibits disability-based discrimination by federal agencies (Section 501), federal contractors (Section 503), recipients of federal funding (Section 504), and federal electronic and information technology (Section 508).
Unruh Civil Rights Act
California's Unruh Civil Rights Act (Civil Code §§ 51-51.3) prohibits business establishments from discriminating against disabled persons and is the state-law vehicle most often paired with ADA Title III claims in California ecommerce-accessibility cases.
Equality Act 2010 (UK)
The Equality Act 2010 is the UK statute that consolidates anti-discrimination law and requires service providers (including ecommerce) to make reasonable adjustments so that disabled persons are not put at a substantial disadvantage.
aria-live region
An `aria-live` region is an HTML element marked with the `aria-live` attribute (value `polite` or `assertive`) that tells assistive technology to announce dynamic content changes to the user without requiring focus to move into the element.
aria-label
`aria-label` is an HTML attribute that provides an accessible name for an element when no visible text label is appropriate — most commonly on icon-only buttons, links, and other controls where the visible UI is purely graphical.
Skip link
A skip link is a hidden-by-default link at the top of a page that becomes visible when keyboard-focused, allowing keyboard and screen-reader users to bypass repetitive navigation and jump straight to the main content.
ARIA landmark
ARIA landmarks are HTML5 semantic elements (`<header>`, `<nav>`, `<main>`, `<aside>`, `<footer>`, `<form>`) and their `role=` equivalents that map to navigable page regions for screen-reader users.
Empty alt attribute (`alt=""`)
An empty `alt` attribute (`alt=""`) on an `<img>` element tells assistive technology that the image is purely decorative and should be skipped — distinct from a missing `alt` attribute, which screen readers announce by reading the filename.
prefers-reduced-motion
`prefers-reduced-motion` is a CSS media query (and matching JavaScript MediaQueryList) that lets sites detect when a user has expressed a preference for reduced motion via OS-level accessibility settings.
Focus trap
A focus trap is a JavaScript pattern that contains keyboard focus inside a modal dialog or other transient container, preventing Tab from leaving the dialog while it is open.
sr-only (screen-reader-only) class
`.sr-only` is a CSS utility class that hides content visually while keeping it readable by screen readers — the standard pattern for adding accessible text labels that should not be visually displayed.
HTML autocomplete attribute
The HTML `autocomplete` attribute on form fields declares the field's expected input type (`email`, `tel`, `address-line1`, etc.) so browsers, password managers, and assistive-tech extensions can pre-populate or assist with form completion.