Link unusual words to their definitions
A word your industry uses one way and everyone else uses another, with no definition anywhere on the page. G55 is the technique of linking that word to its definition, either further down the same page or in a glossary. W3C files it as sufficient for two Level AAA rules, one about unusual words and one about abbreviations, and in both cases only when it is paired with the technique that writes the definition itself. G55 is the link. Something else has to be waiting at the other end of it. The test is narrower than it first sounds as well. At least the first instance of the word has to be a link, and that link has to land on the definition rather than on a page that happens to mention it.
How we find it in an audit
A reviewer reads the page the way somebody outside the industry would and lists the words that would stop them. Terms of art, internal jargon, ordinary words used in a restricted sense, abbreviations on first use. Each one gets checked for a link, and each link gets followed, because a link to a glossary index is not a link to a definition. We check that returning is possible too, since a definition on another page with no way back leaves the reader stranded halfway through your sentence.
How affected users experience it
Readers with cognitive and learning disabilities carry the weight of this, and so does anyone reading in a second language. An undefined term is a full stop. They can leave the page to go and search for it, losing their place, or guess and read the rest of the paragraph on a wrong assumption. Neither of those ends well. A link puts the definition one keystroke away and, when it lives on the same page, one keystroke back.
Passes vs. fails
Passes
The first use of each term links to a plain-language definition, and the definition links back to the place the reader left.
Fails
A remediation notice uses three terms of art and defines none of them anywhere on the site.
Other ways to satisfy this rule
7 guides on this site are filed under 3.1.3 Unusual Words. W3C lists this one as sufficient for that rule only alongside G101, so the pair is what passes and neither half does on its own.
- G62sufficientProvide a glossary for specialized terms
- G70sufficientOffer a dictionary search for specialized content
- G101sufficientDefine words used in an unusual or restricted way
- G112sufficientDefine specialized terms inline where they appear
- H40sufficientMark up term-and-definition pairs as description lists
- H54sufficientMark the defining instance of a term with dfn
This guide is our interpretation of W3C technique G55: Linking to definitions. W3C publishes its techniques as guidance rather than as the standard, and says so on every one of them. The success criterion is what conformance is measured against, and a technique is one documented way to meet it.