Jump to content

Three-letter acronym

From Wikipedia, the free encyclopedia

A three-letter acronym (TLA), or three-letter abbreviation, is as the phrase suggests an abbreviation consisting of three letters. The abbreviation for TLA, TLA, has a special status among abbreviations and to some is humourous since abbreviations that are three-letters long are very common and TLA is, in fact, a TLA.

TLA is autological.

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.


History and origins[edit]

The exact phrase three-letter acronym appeared in the sociology literature in 1975.[1] Three-letter acronyms were used as mnemonics in biological sciences, from 1977[2] and their practical advantage was promoted by Weber in 1982.[3] They are used in many other fields, but the term TLA is particularly associated with computing.[4] In 1980, the manual for the Sinclair ZX81 home computer used and explained TLA.[5] The specific generation of three-letter acronyms in computing was mentioned in a JPL report of 1982.[6] In 1988, in a paper titled "On the Cruelty of Really Teaching Computing Science", eminent computer scientist Edsger W. Dijkstra wrote (disparagingly), "No endeavour is respectable these days without a TLA"[7] By 1992 it was in a Microsoft handbook.[8]


The number of possible three-letter abbreviations using the 26 letters of the alphabet from A to Z (AAA, AAB, ... to ZZY, ZZZ) is 26 × 26 × 26 = 17,576. An additional 26 × 26 × 10 = 6,760 can be produced for each single position allowed to be a digit 0-9, such as 2FA, P2P, or WW2, giving a total of 37,856 such three-character strings.

Out of the 17,576 possible TLAs that can be created using 3 uppercase letters, at least 94% of them had been used at least once in a dataset of 18 million scientific article abstracts. Three-letter acronyms are the most common type of acronym in scientific research papers, with acronyms of length 3 being twice as common as those of length 2 or 4.[9]

In standard English, WWW is the TLA whose pronunciation requires the most syllables—typically nine. The usefulness of a TLA typically comes from its being quicker to say than the phrase it represents; however saying 'WWW' in English requires three times as many syllables as the phrase it is meant to abbreviate (World Wide Web). "WWW" is sometimes abbreviated to "dubdubdub" in speech.[10]

See also[edit]


  1. ^ Levy, M. J. (1975). "Review of The Logic of Social Systems". American Journal of Sociology. 81 (3): 658. doi:10.1086/226119. JSTOR 2777655. The acronyms DSE and DNA have something in common: each is a three-letter acronym.
  2. ^ Seavey, S. R.; Raven, P. H. (1977). "Chromosomal Differentiation and the Sources of the South American Species of Epilobium (Onagraceae)". Journal of Biogeography. 4 (1): 57. Bibcode:1977JBiog...4...55S. doi:10.2307/3038128. JSTOR 3038128. All taxa indicated by three-letter acronyms with strains indicated by a fourth letter if necessary.
  3. ^ Weber, W. A. (1982). "Mnemonic Three-Letter Acronyms for the Families of Vascular Plants: A Device for More Effective Herbarium Curation". Taxon. 31 (1): 74–88. doi:10.2307/1220592. JSTOR 1220592.
  4. ^ Nilsen, K. D.; Nilsen, A. P. (1995). "Literary Metaphors and Other Linguistic Innovations in Computer Language". The English Journal. 84 (6): 65–71. doi:10.2307/820897. JSTOR 820897.
  5. ^ Steven Vickers ZX81 Basic Programming, Sinclair Research Limited, page 161 "As you can see, everything has a three letter abbreviation (TLA)."
  6. ^ TDA Progress Report R. Hull (1982) An Introduction to the new Productivity Information Management System page 176
  7. ^ On the cruelty of really teaching computer science
  8. ^ Dan Gookin (1992) The Microsoft Guide to Optimizing Windows page 211
  9. ^ Barnett, Adrian; Doubleday, Zoe (2020-07-23). Rodgers, Peter (ed.). "The growth of acronyms in the scientific literature". eLife. 9: e60080. doi:10.7554/eLife.60080. ISSN 2050-084X. PMC 7556863. PMID 32701448.
  10. ^ "DigiSpeak: A Glossary of the New Lingo". bryn mawr alumnae bulletin. Bryn Mawr College Alumnae Association. May 2011. Retrieved August 14, 2016.