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Accessibility Glossary
Quick reference for accessibility and screen reader terminology. Each term links to deeper coverage elsewhere in the docs.
A
Accessibility Tree- The browser's parallel data structure exposing roles, names, and states to assistive technology. Learn more
ARIA (Accessible Rich Internet Applications)- W3C spec for enhancing HTML semantics when native elements are insufficient. Learn more
aria-live- Attribute that marks regions for automatic announcement when content changes. Learn more
Assertive- Live region priority that interrupts current speech immediately. Learn more
Assistive Technology- Software or hardware enabling people with disabilities to use computers: screen readers, switch devices, magnifiers. Learn more
B
Browse Mode- Screen reader mode for reading all page content linearly using a virtual cursor. Learn more
C
Combobox- Composite widget combining a text input with a popup list of selectable options. Learn more
Computed Name- The accessible name determined by the browser's name computation algorithm. Learn more
D
Dialog- Overlay container requiring user interaction before returning focus to the page. Learn more
Document Structure- Roles that organize page content hierarchically: headings, lists, tables, and sections. Learn more
F
Focus Mode- Screen reader mode for interacting with form controls and interactive widgets. Learn more
Focus Trap- Pattern constraining Tab navigation within a container, commonly used in modals. Learn more
Focusable- Element capable of receiving keyboard focus, either natively or via tabindex. Learn more
H
Heading Hierarchy- Sequential structure of h1-h6 elements providing document outline for navigation. Learn more
I
Implicit Role- The default ARIA role assigned to an element by its HTML element type. Learn more
Interactive Element- Element users can operate via keyboard or pointer input (buttons, links, inputs). Learn more
K
Keyboard Navigation- Navigating an interface using only keyboard input: Tab, arrows, Enter, Escape. Learn more
L
Landmark- Named page region for quick navigation: main, nav, aside, header, footer. Learn more
Live Region- DOM area that announces content changes to screen readers without focus movement. Learn more
M
Mixed State- Checkbox with aria-checked="mixed" indicating partial selection in a group. Learn more
N
Name Computation- Algorithm browsers use to determine an element's accessible name from multiple sources. Learn more
P
Polite- Live region priority that waits until current speech finishes before announcing. Learn more
Programmatic Focus- Moving focus via JavaScript rather than user interaction, used for dynamic UI updates. Learn more
R
Role- ARIA semantic type assigned to an element, defining its purpose and behavior. Learn more
Roving Tabindex- Focus management pattern for composite widgets using arrow key navigation between items. Learn more
S
Screen Reader- Assistive technology that converts visual UI to synthesized speech or braille output. Learn more
Skip Link- Hidden navigation aid allowing keyboard users to bypass repetitive content blocks. Learn more
State- Dynamic property of an element reflecting its current condition: expanded, checked, disabled. Learn more
T
Tab Order- Sequence in which elements receive focus when the user presses the Tab key. Learn more
Tabindex- HTML attribute controlling whether and in what order an element is focusable. Learn more
V
Virtual Cursor- Screen reader's browse-mode navigation pointer for reading non-interactive content. Learn more
W
WCAG- Web Content Accessibility Guidelines: the international standard for web accessibility. Learn more
Widget Role- ARIA role indicating interactive control behavior (button, slider, tab, etc.). Learn more
Related Pages
How Screen Readers Work
Understand the rendering pipeline from DOM to speech output.
ARIA Roles
Complete reference for ARIA roles, states, and properties.
API Reference
Core library API for analyzing and predicting screen reader output.
Testing Checklist
Step-by-step checklist for manual and automated accessibility testing.