What Is an Acronym? Definition and Examples

An acronym is a word formed from the initial letters of a name (for example, NATO, from North Atlantic Treaty Organization) or by combining the initial letters of a series of words (radar, radio detection, and ranging). Adjective: acronymic. Also called a protogram.

Strictly speaking, says lexicographer John Ayto, an acronym “denotes a combination pronounced as a word . . . rather than as just a sequence of letters” (A Century of New Words, 2007).

An anacronym is an acronym (or another initialism) for which the expanded form isn’t widely known or used, such as OSHA (Occupational Safety and Health Administration).


From the Greek, “point” + “name.”