Glossary · Accessibility term
Accessibility
Accessibility means building websites and tools so that people with disabilities can use them. W3C puts it more precisely, as being able to perceive, understand, navigate and interact with the web, and to contribute to it. That last verb is the half most sites forget. A page can be perfectly readable and still carry a comment box, a review form or an upload that nobody using a screen reader can complete. The range it has to cover is wider than the obvious cases too, taking in auditory, cognitive, neurological, physical, speech and visual disabilities. And it is measured rather than felt. The measure is WCAG, the level laws and contracts reach for is almost always AA, and in a great many countries some version of this is required by law.
In practice
In web work the word has a testable meaning, which is unusual for a word this broad. WCAG 2.2 turns it into 55 success criteria at Level A and AA, each one met or not met on a given page, and an older version of the standard gives you a different count. That is what lets a contract name it and an auditor check it. It is also where the honest limit of the whole exercise sits, and W3C states that limit plainly. Meeting every criterion at all three levels still will not make content usable by people with every type, degree and combination of disability.
It covers permanent disabilities, temporary ones like a broken wrist or an eye infection, and situational limits like bright sunlight or holding a baby with one arm. The same decisions serve all three, which is why accessible sites tend to be better sites generally. Captions serve deaf viewers and everybody in a loud room. Targets big enough to hit serve people with tremors and everybody on a moving train.
Three words get used interchangeably and should not be. Accessibility is specifically about disability barriers and has a standard behind it. Usability is about whether a thing is effective and satisfying for anybody at all. Inclusive design is a method for designing so that fewer people get excluded in the first place. Passing the first tells you very little about the other two, and a site can pass every rule and still be miserable to use.
Why it matters
On a human level, a great deal of ordinary life now happens on the web, so a barrier on your site is somebody unable to do a thing they had every right to do. Pay a bill. Book an appointment. Read what they just agreed to. On a business level, the numbers are large enough that nobody can file this under niche. The World Health Organization put the number of people living with a significant disability at 1.3 billion in March 2023, about 16% of the world, or one in six. Specialist equipment is only part of that picture. Plenty of the people in it are meeting your site with the text turned up, or one hand, or the sound off, and no assistive software involved at all.
The plain test
Can somebody who cannot see your site, cannot use a mouse, or cannot hear your video still do what they came to do? Then ask the second half of it. Can they leave a review, upload a document, or open an account? Reading is the part everybody tests. Contributing is the part that fails.
Where this shows up on the site
Related terms
- a11ya11y is shorthand for the word accessibility, and it means that and nothing narrower.
- WCAGWCAG is the international standard for web accessibility, published by the W3C.
- Level A, AA, AAALevel A, AA and AAA are WCAG's three conformance levels, and they stack.
- DisabilityDisability results from the interaction between a health condition and the world around it.
- Inclusive designInclusive design means treating the full range of human variation as the starting point rather than as an edge case to accommodate once the design is finished.
- Universal designUniversal design is the idea that one design should work for as many people as possible without anybody needing a special version or a separate adaptation.
Knowing the word is the easy part.
Find out where your own site stands. The free scan checks 10 pages in a real browser against all 90 supported automated rules, separates 27 best-practice checks from its WCAG findings, and names the rule behind every result.