Accessibility Glossary

The practice of making websites, tools, and technologies usable by people with disabilities. Also known as a11y (a + 11 letters + y).

Accessible Rich Internet Applications. A set of attributes that can be added to HTML to enhance accessibility for assistive technologies, particularly for dynamic content and custom widgets.

Alternative text that describes images for screen reader users. Required for informative images, should be empty for decorative images.

Any device, software, or equipment that helps people with disabilities interact with computers and digital content. Examples include screen readers, voice recognition software, and switch controls.

The difference in luminance between text and its background. WCAG requires a minimum ratio of 4.5:1 for normal text (Level AA) to ensure readability.

A visual indicator that shows which element currently has keyboard focus. Essential for keyboard navigation and required by WCAG 2.4.7.

The proper nesting of heading elements (h1-h6) to create a logical document structure. Screen readers use headings to navigate content.

The ability to navigate and interact with a website using only a keyboard, without a mouse. Required for users with motor disabilities and essential for WCAG compliance.

ARIA regions that identify major sections of a page (navigation, main, banner, etc.). Help screen reader users understand page structure.

The four principles of WCAG: Perceivable, Operable, Understandable, and Robust. All WCAG guidelines fall under one of these principles.

Assistive technology software that reads aloud content displayed on a computer screen. Popular examples include NVDA, JAWS, and VoiceOver.

HTML elements that convey meaning about their content (e.g., <nav>, <main>, <article>). Preferred over generic <div> elements for accessibility.

A link that allows keyboard users to skip repetitive navigation and jump directly to main content. Improves navigation efficiency.

A testable statement that defines what must be achieved to meet a WCAG guideline. Each criterion has a level (A, AA, or AAA).

The interactive area of a button or link on touch devices. WCAG 2.5.8 (Level AA) requires a minimum size of 24x24 CSS pixels, while WCAG 2.5.5 (Level AAA) requires 44x44 CSS pixels for touch targets.

Web Content Accessibility Guidelines. International standards developed by the W3C to make web content accessible to people with disabilities.

An ARIA region that announces dynamic content changes to screen reader users without requiring them to navigate to that area.

A technique that keeps keyboard focus within a modal or dialog until it's closed, preventing users from tabbing to background content.

A visual impairment affecting the ability to distinguish certain colors. WCAG requires that color not be the only means of conveying information.

Text versions of spoken content in videos, synchronized with the audio. Required for WCAG Level A compliance for pre-recorded video content.

A text version of audio or video content. Provides an alternative way to access information for deaf and hard-of-hearing users.

Text that identifies the purpose of a form input. Must be programmatically associated with the input using <label> or aria-labelledby.

Text that identifies form validation errors. Must be programmatically associated with the input and clearly describe the error.

ARIA roles that identify major page regions (banner, navigation, main, complementary, contentinfo). Help users navigate page structure.

The sequence in which elements receive focus when navigating with a keyboard. Must follow a logical order that matches the visual layout.

A development approach that starts with basic, accessible HTML and adds layers of enhancement (CSS, JavaScript) while maintaining core functionality.

Ensuring that websites remain functional even when advanced features fail or aren't supported. Important for accessibility and compatibility.

Assistive technology that allows users to control computers and navigate websites using voice commands instead of a keyboard or mouse.

An assistive technology that allows users to interact with devices using switches, often used by people with limited mobility.

A tactile device that converts screen content into Braille characters, used by blind and visually impaired users alongside screen readers.