Offer a dictionary search for specialized content
Put a lookup on the page and let a reader query an online dictionary without leaving. G70 is that technique, and W3C files it as sufficient for two Level AAA rules, one on unusual words and one on abbreviations, and in both cases only alongside the technique that supplies the definition. So it supplements a definition mechanism rather than standing in for one. There is a condition that decides whether it works at all. The dictionary has to return the right definition for your content, and a general dictionary often will not. A site about computing needs a computing dictionary, because the general one defines a word your readers already knew and misses the sense you meant.
How we find it in an audit
Where a lookup exists, we test it on the words that genuinely caused trouble rather than on easy ones. Terms of art, internal jargon, abbreviations, ordinary words used in a restricted sense. The only question that matters is whether the definition coming back is the one your content meant. We also check the mechanism reaches every page carrying those terms, and that using it does not cost the reader their place in what they were reading.
How affected users experience it
Leaving the page to search costs a screen-reader user more than it costs a sighted one, because coming back means finding the sentence again in a page they navigate by heading rather than by eye. A lookup on the page removes that trip. It is not the strongest answer available, though, and that is worth saying. An inline definition or a glossary entry puts the meaning in front of the reader, where a search asks them to go and fetch it.
Passes vs. fails
Passes
Selecting any word offers Look up in dictionary, and the definition opens beside the text rather than in place of it.
Fails
A literature archive full of archaic vocabulary offers no lookup, so readers juggle a second tab for every unfamiliar word.
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.
- G55sufficientLink unusual words to their definitions
- G62sufficientProvide a glossary for specialized terms
- 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 G70: Providing a function to search an online dictionary. 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.