Glossary
Plain-language definitions of the key terms used in this handbook.
- Accessibility
- Designing content so people with the widest range of abilities can perceive, understand, and use it.
- Assistive technology
- Hardware or software people use to access content, such as screen readers, magnifiers, or voice control.
- Alt text (alternative text)
- A short written description of an image, read aloud by screen readers.
- Screen reader
- Software that reads on-screen text and alt text aloud (e.g. NVDA, VoiceOver, TalkBack).
- Captions
- On-screen text of a video’s speech and important sounds, for viewers who cannot hear the audio.
- Subtitles
- On-screen text of speech only, usually a translation, assuming the viewer can hear.
- Audio description
- Narration of a video’s important visual content for blind and low-vision viewers.
- Transcript
- A full written version of audio (or audio + visuals) content.
- Contrast ratio
- A measure of how much text stands out from its background; AA requires 4.5:1 (3:1 for large text).
- Decorative image
- An image that adds no information; its alt text can be empty.
- Informative image
- An image that carries meaning; it must have descriptive alt text.
- Plain language
- Clear, simple writing using short sentences and common words.
- WCAG
- Web Content Accessibility Guidelines — the international standard for digital accessibility.
- POUR
- The four WCAG principles: Perceivable, Operable, Understandable, Robust.
- Conformance level
- How fully content meets WCAG: A (minimum), AA (standard), AAA (highest).
- Tagged PDF
- A PDF with hidden structure (tags) so screen readers can read it in the correct order.
- VPAT / ACR
- Voluntary Product Accessibility Template / Accessibility Conformance Report — a standard document in which a vendor states how well a product meets accessibility standards (Supports / Partially Supports / Does Not Support).
- Accessibility statement
- A short public notice of an organization’s accessibility commitment, the standard it targets, and how to report a barrier or request another format.
- CamelCase
- Writing multi-word hashtags with each word capitalized, e.g. #WorldDisabilityDay.
- Live captions
- Real-time on-screen text of what is being said during a live event or webinar.
- Induction (hearing) loop
- A venue sound system that sends audio directly to hearing aids set to the “T” position.