An abbreviation is marked up as follows:
The <abbr> tag defines an abbreviation or an acronym, like "Mr.", "Dec.", "ASAP", "ATM".
Tip: An abbreviation and an acronym are both shortened versions of something else. Both is often represented as a series of letters.
Marking up abbreviations can give useful information to browsers, translation systems and search-engines.
Tip: The global title attribute can be used in the <abbr> tag to show the full version of the abbreviation/acronym when you mouse over the <abbr> element.
The <abbr> tag also supports the Global Attributes in HTML.
The <abbr> tag also supports the Event Attributes in HTML.
HTML DOM reference: Abbreviation Object