Abbreviations

What it asks

Any abbreviation — acronyms (NASA), initialisms (HTML), shortened forms (Dr., approx.) — must have a way for readers to find the expanded form or meaning. The expansion can appear inline on first use, in a glossary, via a tooltip on <abbr title>, or any equivalent technique.

When the same abbreviation can mean different things in different contexts (PC = personal computer, political correctness, polycarbonate), the page must disambiguate too.

How to meet it

• Spell out the abbreviation on first use, followed by the abbreviation in parentheses: “World Health Organization (WHO).” Subsequent uses can stand alone.
• Wrap the abbreviation in <abbr title="World Health Organization">WHO</abbr> so the title shows on hover and is exposed to assistive technology.
• For abbreviations that recur across many pages, maintain a glossary and link to it.
• For ambiguous abbreviations, use one of the techniques above to make the specific meaning clear.
• Avoid relying on <abbr title> alone if the abbreviation is critical — tooltips are unreliable on touch and the title attribute is not consistently announced.

Common failures

• Acronyms used throughout a document without ever being expanded.
• Abbreviations expanded only at the very end of a long document, where the reader has already lost context.
• <abbr> elements without a title attribute — semantically marked but no expansion provided.
• Industry-specific abbreviations (KPI, ARR, OKR, MAU) treated as common knowledge in public-facing content.

Why it matters

Screen readers can be configured to announce the expansion of <abbr title> automatically, which is one of the few ways the title attribute genuinely earns its keep. For users with cognitive disabilities, learning disabilities, or limited domain knowledge, unexpanded abbreviations are a significant comprehension barrier. The fix is editorial discipline at writing time, with a small markup affordance for screen-reader users.