Three-letter acronym

A three-letter acronym (TLA), or three-letter abbreviation is, as the phrase suggests, an abbreviation consisting of three letters. The term has a special status among abbreviations and to some is considered humorous since the term TLA is itself a three-letter acronym; it is an autological word.

Most TLAs are initialisms (the initial letter of each word of a phrase), but most are not acronyms in the strict sense since they are pronounced by saying each letter, as in APA /ˌpˈ/ AY-pee-AY. Some are true acronyms (pronounced as a word) such as CAT (as in CAT scan) which is pronounced as the animal.