Understandable · 3.1 Readable
A mechanism must be available to identify the expanded form or meaning of abbreviations, including acronyms and initialisms, such as spelling out the first use, linking to a glossary, or using markup like the abbr element.
Live demo
The same task, done two ways: switch between the version that passes and the one that fails, or put them side by side. Everything in the box is live, so try it with a keyboard, a pointer or a screen reader.
Read both versions in the screen reader preview. Only the passing version tells you what IBAN, BIC and SEPA stand for.
The tools follow the version you last used.
What happened
Why it passes
Each abbreviation is spelled out the first time it appears, so a listener hears what IBAN, BIC and SEPA stand for before the fields ask for them.
Why it fails
The abbreviations are never spelled out, so a reader who does not know banking terms cannot tell which details the fields are asking for.
Examples
Four examples, each one running: the usual ways this criterion fails, and code that passes. Listen to them, measure them, or copy the code.
Fails
Live preview
<p>To receive your refund, send us your IBAN and BIC. We pay refunds through SEPA within five working days.</p>IBAN, BIC and SEPA are never expanded, so readers who do not know banking terms cannot tell which details to send.
Passes
Live preview
<p>To receive your refund, send us your International Bank Account Number (IBAN) and Bank Identifier Code (BIC). We pay refunds through the Single Euro Payments Area (SEPA) within five working days.</p>Each abbreviation follows its full form the first time it appears, so every reader sees the meaning without an extra step. Later uses can be the short form. This is technique G97.
Fails
Live preview
<table> <caption>Your order</caption> <tr><th>SKU</th><th>Quantity</th><th>MSRP</th></tr> <tr><td>CH-2041</td><td>2</td><td>$18.00</td></tr></table>The column headers use retail abbreviations that are not explained anywhere, so a shopper cannot tell what SKU or MSRP means.
Passes
Live preview
<table> <caption>Your order. SKU means stock keeping unit and MSRP means manufacturer's suggested retail price.</caption> <tr> <th><abbr title="stock keeping unit">SKU</abbr></th> <th>Quantity</th> <th><abbr title="manufacturer's suggested retail price">MSRP</abbr></th> </tr> <tr><td>CH-2041</td><td>2</td><td>$18.00</td></tr></table>The caption spells out the abbreviations in text everyone can read, and abbr adds the expansion in the markup. A title tooltip alone only appears on mouse hover, so the visible text matters.
Why it matters
People with cognitive, language, or learning disabilities, and readers new to a subject, may not recognize abbreviations. Screen reader users may also hear an abbreviation spelled out or mispronounced without learning what it stands for.
W3C: Understanding 3.1.4Level AAA
Level AAA is the highest level. It is not required for whole sites, but it is worth meeting where you can.
Where it is required
No law on this site requires Level AAA criteria for whole sites.
How to test
A few concrete steps. Automated tools find some failures; most need a person.
Common failures