Web Accessibility Glossary
Key terms for understanding ADA compliance, WCAG guidelines, and website accessibility.
A
ADA (Americans with Disabilities Act)
A federal civil rights law that prohibits discrimination against people with disabilities in all areas of public life, including websites of businesses that are places of public accommodation. Title III of the ADA is most relevant to website accessibility.
Related: Title III, DOJ
Alt Text (Alternative Text)
A text description added to images that screen readers can read aloud. Alt text should describe the content and function of images for users who cannot see them. Missing alt text is one of the most common accessibility violations.
Related: Screen Reader, WCAG
ARIA (Accessible Rich Internet Applications)
A set of HTML attributes that define ways to make web content more accessible to people with disabilities. ARIA labels, roles, and properties help screen readers understand dynamic content and custom interface components.
Related: Screen Reader, WAI
Assistive Technology
Any device, software, or equipment that helps people with disabilities use computers and the internet. Examples include screen readers, screen magnifiers, voice recognition software, and alternative keyboards.
Related: Screen Reader, JAWS, NVDA
Audit (Accessibility Audit)
A comprehensive evaluation of a website's accessibility, typically checking against WCAG guidelines. Audits can be automated (using scanning tools) or manual (using assistive technology and expert review).
Related: WCAG, Remediation
C
Caption
Text displayed on video content that shows dialogue and important sounds. Captions are essential for deaf and hard-of-hearing users. They differ from subtitles, which only show dialogue.
Related: Transcript, Audio Description
Color Contrast
The difference in brightness between foreground text and background colors. WCAG requires a minimum contrast ratio of 4.5:1 for normal text and 3:1 for large text to ensure readability for users with low vision or color blindness.
Related: WCAG, Low Vision
D
Demand Letter
A formal letter from an attorney threatening legal action over alleged ADA website violations. Demand letters typically request a settlement payment and website remediation. They are often the first step before a lawsuit.
Related: ADA, Settlement
DOJ (Department of Justice)
The federal agency responsible for enforcing the ADA. The DOJ has issued guidance stating that websites of public accommodations must be accessible and has pursued enforcement actions against inaccessible websites.
Related: ADA, Title III
F
Focus Indicator
A visible outline or highlight that shows which element on a webpage is currently selected when navigating with a keyboard. Focus indicators are essential for keyboard-only users to know where they are on the page.
Related: Keyboard Navigation, WCAG
Form Label
Text that identifies and describes a form input field. Proper labels are associated with their inputs so screen readers can announce what information is being requested. Missing form labels are a common accessibility violation.
Related: Screen Reader, ARIA
H
Heading Structure
The hierarchical organization of headings (H1-H6) on a webpage. Proper heading structure helps screen reader users navigate and understand page content. Headings should follow a logical order without skipping levels.
Related: Screen Reader, Navigation
J
JAWS
Job Access With Speech - one of the most popular commercial screen readers for Windows. JAWS reads text on the screen aloud and is commonly used by people who are blind or have low vision.
Related: Screen Reader, NVDA, VoiceOver
K
Keyboard Navigation
The ability to navigate and interact with a website using only a keyboard, without requiring a mouse. Essential for users with motor disabilities and those using screen readers. All interactive elements must be keyboard accessible.
Related: Tab Order, Focus Indicator
L
Link Text
The clickable text of a hyperlink. Descriptive link text (like 'Read our privacy policy') is more accessible than vague text (like 'click here') because it tells users where the link goes without needing surrounding context.
Related: Screen Reader, WCAG
N
NVDA
NonVisual Desktop Access - a free, open-source screen reader for Windows. NVDA is widely used for accessibility testing and by people who are blind or have low vision.
Related: Screen Reader, JAWS, VoiceOver
O
Overlay (Accessibility Overlay)
Third-party tools that claim to automatically fix website accessibility issues by adding a layer on top of existing code. Overlays are controversial because they often don't fully resolve accessibility issues and can interfere with assistive technology.
Related: Remediation, WCAG
P
PDF Accessibility
Making PDF documents readable by screen readers through proper tagging, reading order, alt text for images, and document structure. Many PDFs are created as images or lack proper tags, making them inaccessible.
Related: Tagged PDF, Screen Reader
R
Remediation
The process of fixing accessibility issues on a website to bring it into compliance with WCAG guidelines and ADA requirements. Remediation may involve code changes, content updates, and structural improvements.
Related: Audit, WCAG
S
Screen Reader
Software that reads website content aloud for users who are blind or have low vision. Screen readers interpret HTML structure, alt text, ARIA labels, and other accessibility features to convey information audibly.
Related: JAWS, NVDA, VoiceOver
Section 504
Part of the Rehabilitation Act of 1973 that prohibits discrimination based on disability in programs receiving federal funding. Applies to schools, hospitals, and organizations that receive federal grants or contracts.
Related: Section 508, ADA
Section 508
Part of the Rehabilitation Act requiring federal agencies to make their electronic and information technology accessible. Section 508 standards are often used as benchmarks even by non-federal organizations.
Related: Section 504, WCAG
Skip Link
A hidden link at the top of a webpage that allows keyboard users to skip repetitive navigation and jump directly to main content. Skip links improve efficiency for users who navigate with keyboards or screen readers.
Related: Keyboard Navigation, Navigation
T
Tab Order
The sequence in which elements receive focus when a user presses the Tab key. Proper tab order should follow the visual layout of the page and make logical sense for keyboard navigation.
Related: Keyboard Navigation, Focus Indicator
Tagged PDF
A PDF document with embedded structure tags that identify headings, paragraphs, lists, tables, and other elements. Tagged PDFs are accessible to screen readers, while untagged PDFs are often completely inaccessible.
Related: PDF Accessibility, Screen Reader
Title III
The section of the ADA covering public accommodations - businesses open to the public such as restaurants, hotels, retail stores, and their websites. Title III is the basis for most website accessibility lawsuits.
Related: ADA, DOJ
Transcript
A text version of audio or video content. Transcripts allow deaf users to access spoken content and help all users search, reference, and consume content in text form.
Related: Caption, Audio Description
V
VoiceOver
Apple's built-in screen reader for macOS, iOS, and iPadOS. VoiceOver is commonly used for accessibility testing on Apple devices and by people who are blind or have low vision.
Related: Screen Reader, JAWS, NVDA
VPAT (Voluntary Product Accessibility Template)
A document that explains how a product or service conforms to accessibility standards. VPATs are commonly requested during procurement to evaluate vendor accessibility compliance.
Related: Section 508, WCAG
W
WAI (Web Accessibility Initiative)
The W3C initiative that develops accessibility standards and guidelines including WCAG. WAI brings together organizations worldwide to develop strategies, guidelines, and resources for web accessibility.
Related: W3C, WCAG
WCAG (Web Content Accessibility Guidelines)
International standards for web accessibility developed by the W3C. WCAG 2.1 Level AA is the most commonly referenced standard for ADA compliance. Guidelines are organized around four principles: Perceivable, Operable, Understandable, and Robust.
Related: W3C, WAI, Level AA
WCAG Level A
The minimum level of WCAG conformance. Level A criteria address the most basic accessibility requirements. Failing Level A typically means content is completely inaccessible to some users.
Related: WCAG, Level AA, Level AAA
WCAG Level AA
The mid-level of WCAG conformance and the standard most commonly required for legal compliance. Level AA includes all Level A criteria plus additional requirements for color contrast, text resizing, and navigation.
Related: WCAG, Level A, Level AAA
WCAG Level AAA
The highest level of WCAG conformance with the strictest accessibility requirements. Level AAA is not typically required for legal compliance but represents best practices for maximum accessibility.
Related: WCAG, Level A, Level AA
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