Three-letter Initialisms

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I spent last week at the ASA conference in Nashville. The "ASA", as members all call it, is the Acoustical Society of America — but is "American Students' Assistance", while is the "American Sailing Association", and Wikipedia offers 75 other options for the ASA initialism.

This is general problem. Another organization that I belong to is the LSA, as the members of the Linguistic Society of America call it — but is the "Louisiana Sheriffs' Association", and is apparently malware associated with Windows' Local Security Authority, so I won't link to it. The Linguistic Society of America, having been pre-empted by the Louisiana Sheriffs, used to be online at the URL, but is now Wikipedia offers 48 other options for LSA. They include "Latent Semantic Analysis", which is the earliest of the word-embeddings at the root of the tree whose recent fruits include ChatGPT — which recently evoked some confusion on this blog as to the meaning of the GPT initialism.

There are obviously 26^3 = 17576 three-letter initialisms, and nearly all of them are spoken for, multiple times over.

Web (and Wikipedia) search suggests that nearly all possible 3-letter sequences are Out There — though some, like AZU, are words or names, which makes it harder to find many uses as initialisms or acronyms. Someone with more patience than I have could estimate how they're divided up among various types of initialisms: companies, organizations, concepts, algorithms, methods, diseases, drugs, and so on.

To help explore this issue, I wrote a little program to generate random 3-letter sequences. Here's 1001 outputs.

There's also the question of how many such initialisms a reasonably literate person knows. Obviously this will vary a lot from person to person, but I'm guessing it's generally over 100.



  1. Dick Margulis said,

    December 11, 2022 @ 4:36 pm

    TMI. (LOL)

  2. David Marjanović said,

    December 11, 2022 @ 4:36 pm

    Shouldn't this post have been called "TLAs" or "TLIs"?

  3. Uly said,

    December 11, 2022 @ 4:38 pm

    On a VERY tangential note, I have a dyslexic niece who consistently gets wrong any initialism she learned after she learned how to read. So "TV" is fine, but "CVS" or "NAACP" or "PCOS" are a crapshoot at best. If she's lucky she gets the right letters but in the wrong order.

  4. Mark Liberman said,

    December 11, 2022 @ 5:09 pm

    @Dick Margolis: Do you mean "Three Mile Island"? or "Toastmasters International"? or "Taiwan Music Institute"? or "TriMethylIndium"?

    Seriously, these initialisms are always THO ("too heavily overloaded")…

  5. Dick Margulis said,

    December 11, 2022 @ 5:23 pm

    @Mark Lieberman: Too Many Instances ;-)

  6. Fernando said,

    December 11, 2022 @ 5:23 pm

    I wonder why we use these so much. It used to be “acid reflux”, now it’s GIRD. An enlarged prostate is BPH. Words are better than letters!

    My wife has the problem of getting these out of order, occasionally puzzling me. By now I know what she maens by PSTD and others.

    Professional associations I belong to include AMS, MAA, HSS, SMF. All of which have many alternative meanings.

  7. J.W. Brewer said,

    December 11, 2022 @ 5:35 pm

    By contrast only about 45 rivals are listed by wikipedia for AAS, which would be the initialism for the hypothetical American Acoustical Society. I can't figure out what if any pattern there is in the choice of the "Judean People's Front" construction versus the "People's Front of Judea" construction, although obviously there are numerous contexts in which both exist side by side in competition with each other.

  8. David C said,

    December 11, 2022 @ 5:56 pm

    Of course there is the ultimate three letter acronym, which we used often when I was in a fortune 100 company: TLA

  9. David C Staples said,

    December 11, 2022 @ 6:53 pm

    "The note was signed Albert Gibbs RA. On my return I questioned him about the initials after his name, saying that I had no idea he was an artist, and Royal Academician at that! 'No, no,' he demurred, 'RA stands for Royal Artillery.' Apparently he had served the the Royal Artillery during the First World War.
    Similarly, Albrecht Dürer's renowned monogram, AD, together with the date, was intended as a pun on Anno Domini. The various possible interpretations of any given set of initials has from time to time caused real embarrassment to experts, and not only in the field of art. For example, after a lengthy study of what he believed to be an ancient pot inscribed MJDD, a member of the French Academy of Inscriptions was able to decipher the initials as an appreviation of the phrase Magno Jovi Deorum Deo ('To the Great Jupiter, God of Gods'). This scholar was somewhat discomfited to learn later that the pot was not an antiquity at all byt a modern mustard jar, and the letters stood for Moutard Jaune de Dijon (Yellow Dijon Mustard)."

    Eric Hebborn, The Art Forger's Handbook (Cassel 1997) p.68.

  10. Erin B. said,

    December 11, 2022 @ 7:40 pm

    Definitely a problem at the Folger Shakespeare Library, where I work. The librarians have the Society of American Archivists, the scholars have the Shakespeare Association of America, and the scholar-librarians have both. Twice a year, the question "Are you going to SAA?" causes at least one person to hyperventilate because they think they didn't have it on their calendar.

  11. MattF said,

    December 11, 2022 @ 9:02 pm

    I wonder if there’s any pattern in initialism errors. Are errors mainly two-letter transpositions? Does pronouncibility matter? It looks like all long-term memory and single-letter correlations with very weak semantic constraints.

  12. david said,

    December 11, 2022 @ 9:07 pm

    @Mark Lieberman @Dick Margolis Too Much Information

  13. Dick Margulis said,

    December 11, 2022 @ 9:55 pm

    @david: Yes, I know. And, yes, I'm sure Mark Liberman knows. But now you've managed to reproduce the misspellings of both of our names.

  14. David Morris said,

    December 12, 2022 @ 12:20 am

    My father said he witnessed a man signing as 'Fred Nurks BA'. When he asked if he'd been to university, he said 'No, I'm a boiler attendant'.

  15. Lara P. said,

    December 12, 2022 @ 3:35 am

    In computing circles, these have been long-known as TLAs – for Three-Letter Abbreviation (or Acronym).

    While things like NATO or HTML are known as ETLAs – Extended Three-Letter Abbreviation.

  16. Mark P said,

    December 12, 2022 @ 9:32 am

    Lara P. hits close to my question, how do four-letter abbreviations compare to three-letter abbreviations, aside from having more possibilities?

  17. Robert Coren said,

    December 12, 2022 @ 10:19 am

    I was somewhat taken aback by a note on a flyer for an event at the retirement community to which we have just moved, advising that RSVPs should go to "[first-name] [last-name], RSC @ [phone-number]" because my immediate reaction was "Why are my initials in this notice?" (I assume the initialism actually stands for "Resident Services Coordinator" or some such.)

    When I first visited London many years ago, I was similarly taken aback to see my initials on posters plastered all over the city (actually advertising the Royal Shakespeare Company, of course).

  18. Jake Wildstrom said,

    December 12, 2022 @ 11:40 am

    I'm a member of two different organizations calling themselves the DSA. They're both ambitious in their plans to reshape the way Americans live their lives, but only one of them wants us to have two new numerals.

  19. Coby said,

    December 12, 2022 @ 12:24 pm

    To me the most annoying TLI is IPA, which stands for both the International Phonetic Association and its own creature, the International Phonetic Alphabet, which incidentally is not international (since it deals with languages, not nations), not phonetic (it's phonemic at best), and not an alphabet (since it has no alphabetic order).

  20. Taylor, Philip said,

    December 12, 2022 @ 1:17 pm

    … and worse, if one asks for a pint of IPA in one's local hostelry, one is likely to be asked /ɪn ə dʒʌɡ ɔːrə ɡlɑːs sɜː/ if the barman is also a linguist !

  21. Mark Metcalf said,

    December 12, 2022 @ 1:20 pm

    1. Abbreviations are extensively used in Russian and dictionaries (сокращение словарь) are available for 'decoding' them. A good online Russian-Russian dictionary can be accessed at
    2. TLAs were also "three-letter agencies" (e.g. DIA, CIA, NSA)
    3. A source for decoding Naval abbreviations is known as the "DICNAVAB" – the Dictionary of Naval Abbreviations. Published in 1984, it's still available on Amazon.

  22. Victor Mair said,

    December 12, 2022 @ 8:03 pm

    J.W. Brewer:

    For me, an important AAS TLI is Association for Asian Studies. I've been going to their meetings for more than four decades. To be distinguished from the venerable AOS (American Oriental Society).

  23. Linda Seebach said,

    December 13, 2022 @ 9:48 am

    The Associated Press Stylebook allows a (very small) number of TLAs to be used without spelling them out on first reference. I don't have a current edition, but FBI and IRS come to mind. CDC must be irritatingly spelled out as the Centers for Disease Control and Prevention although it's still TLAd as CDC.

  24. Taylor, Philip said,

    December 13, 2022 @ 1:32 pm

    I think that there is a good reason for requiring "CDC" to be glossed at its first occurence — for those of us of a certain age, "CDC" is "Control Data Corporation" (think CDC 6400, 6600, 7600, Cyber 205, …) and always will be.

  25. Peter said,

    December 14, 2022 @ 2:35 pm

    I once worked on some software known as NNCS, which stood for NICS Network Control System; NICS was the NATO Integrated Communication System, and NATO is of course the North Atlantic Treaty Organization. Since then I've been looking for a fourfold nested initialism – in vain.

  26. Barbara Phillips Long said,

    December 14, 2022 @ 5:39 pm

    Then there are the acronyms that originate in languages other than English. Doctors Without Borders, for instance, is MSF, for Médecins Sans Frontières.

  27. Andreas Johansson said,

    December 16, 2022 @ 1:30 am

    Perhaps the one I encounter most frequently is SI, French Système International, or "International System (of units)". Given the notoriety of a certain jihadist outfit in recent years, it's perhaps a good thing they didn't go for the English.

  28. Randy Hudson said,

    December 16, 2022 @ 12:21 pm

    Then there's UTC, a compromise between English "coordinated universal time" and French "temps universel coordoné".

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