Understanding WCAG2.0

If there is an abbreviation in the content, you can know the original word or meaning of the abbreviation. It can be said that it is also related to 3.1.3. Incidentally, in HTML 4.01, there are tags abbr (abbreviation .eg XML, HTML), acronym (acronym .eg LAN, NATO), which are markups of abbreviations and meaning that meaning abbreviations expanded with the title attribute Yes, but somewhat accessible and supported situation is awkward, so be careful.

In HTML5, acronym is obsolete. Let's mark up with abbr in HTML5.

Principle Understandable Information and the operation of user interface must be understandable.
Guideline Readable Make text content readable and understandable.
Criterion Abbreviations
(3.1.4 AAA)
Mechanisms can be used to identify the original word or meaning of the abbreviation.

URL of Techniques for WCAG 2.0