Accessibility Definition: What It Means in Tech

What is accessibility?

Accessibility means designing and building websites, apps and software so that people with disabilities can use them. The W3C Web Accessibility Initiative puts it as sites, tools and technologies that are designed and developed so that people with disabilities can use them. It covers vision, hearing, movement, speech and cognitive needs, and it also helps people in temporary or situational limits, such as glare on a phone screen or a room where audio cannot play.

How it works in practice

Most web accessibility work follows WCAG, the Web Content Accessibility Guidelines. WCAG 2.2 is also published as ISO/IEC 40500. Its four principles are perceivable, operable, understandable and robust (see POUR). In practice that means:

• Text alternatives for images, so a screen reader can describe them (see accessible images).
• Full keyboard operation with a visible focus indicator.
• Enough colour contrast and no information carried by colour alone (see accessible colour palettes).
• Captions or transcripts for audio and video.
• Semantic HTML, with ARIA only where native elements fall short.

Example

A checkout form with a visible label on every field, errors written in text next to the field, and a button reachable with Tab and Enter works for a screen reader user, a keyboard-only user and someone on a phone in bright sunlight. The same form with placeholder-only labels and red borders as the only error signal fails all three.

Common mistakes

• Treating accessibility as a final audit instead of a design and component-level habit.
• Relying on an automated scanner alone. Automated tools catch only part of the issues, so keyboard and assistive technology checks are still needed.
• Adding ARIA to fix markup that should simply be a native button or link.
• Confusing accessibility with usability for the average user: the two overlap, but accessibility has testable criteria.

Accessibility and testing

Accessibility is checked with automated scans, manual keyboard and screen reader passes, and conformance reporting such as an accessibility conformance report or a VPAT. Our comparison of website accessibility testing tools shows what each approach finds, and why performance testing should include accessibility covers the overlap with speed work. Page speed monitoring tracks the Lighthouse accessibility score of your pages over time, which helps you catch regressions. It does not replace a manual review.

FAQ

What is the simplest definition of accessibility?

Accessibility means people with disabilities can perceive, understand, navigate and interact with a product on equal terms with everyone else.

Is accessibility the same as WCAG compliance?

No. WCAG is the main technical standard, but accessibility also covers real use with assistive technology and the choices made in design and content. Passing every WCAG criterion is a strong baseline, not a guarantee that every user succeeds.

Who benefits from accessible design?

People with permanent disabilities first, but also older users whose abilities change, people with a broken arm or a noisy room, and anyone on a small screen in bright light.

Is accessibility a legal requirement?

In many places, yes. For example, the European Accessibility Act covers services such as online shopping and banking. Check the rules that apply to your market and ask a qualified adviser for legal questions.

How do I start testing for accessibility?

Run an automated scan, then tab through the page with the keyboard, zoom to 200%, and try a screen reader on your key flows. Fix issues in shared components first.