Abbreviations
A mechanism for identifying the expanded form or meaning of abbreviations is available.
In plain language
Whenever an abbreviation is used, there should be a way to find out what it stands for — unless it's become a common word on its own (like "laser").
Why it matters
Not everyone recognizes every abbreviation, and people with memory or cognitive disabilities may not be able to hold onto or infer its meaning from context. A simple way to look up the full form removes that guesswork.
In practice
Fails this criterion
A medical article uses an abbreviation repeatedly throughout, without ever spelling out what it means anywhere on the page.
Meets this criterion
The same page introduces the term with its full name and abbreviation together the first time it's used, so readers know exactly what it stands for.
Test it yourself
Look for abbreviations in the site's content. Is the full meaning available somewhere (spelled out on first use, a glossary, a tooltip)? If an abbreviation is used with no way to find its meaning, this criterion is failing.