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One question I often field in my capacity as OUP’s editor for American dictionaries is, “What’s the longest word in the dictionary?” I don’t hear it as often as “How do I get a new word in the dictionary?” but it still comes up from time to time. My stock answer isn’t very interesting: “It depends on what counts as a ‘word,’ and it depends on the dictionary.” That answer doesn’t satisfy most people, since the follow-up question is typically something like, “No, really, is it antidisestablishmentarianism or supercalifragilisticexpialidocious?” Those two specimens are the “usual suspects” that get hauled out in discussions of the longest word in English, perhaps because most of us have been familiar with them since grade school. But there are many other worthy candidates for the “longest word” mantle.

First, some ground rules. Let’s say that a “word” is a single lexical item that is unbroken by spaces or hyphens. That’s a rather arbitrary distinction, but it accords with most people’s judgments of wordhood. (When the New Oxford American Dictionary named carbon neutral the 2006 Word of the Year, there were numerous complaints that this is actually two words.

One of the best-known long-word pioneers! Image Credit: ‘Mary Poppins at Disneyland Park in Anaheim, CA’, Photo by Jonnyboyca, Public Domain, via Wikimedia Commons.

But as Oxford English Dictionary editor at large Jesse Sheidlower pointed out in another context, promoting the “Lexical Item of the Year” doesn’t have quite the same ring to it.) By those standards, the longest word that has entered any major English dictionary is this 45-letter whopper: pneumonoultramicroscopicsilicovolcanoconiosis, meaning ‘a lung disease caused by inhaling very fine ash and sand dust.’ You can find it under the prefix pneumono- in the online edition of the Oxford English Dictionary, as well as the Shorter Oxford English Dictionary.

There’s only one problem with P45, as it’s known to its friends: it’s most likely a fabrication. As described in an article in the magazine Word Ways, the word appears to have been invented on the occasion of a 1935 meeting of the National Puzzlers League in New York. The NPL’s president at the time, Everett M. Smith, presented it as “the longest word in the English language.” But there’s not a shred of evidence that the word was used in medical literature before Smith unveiled it at the NPL meeting and the press picked up on the fanciful story. It looks like Smith simply made it up. Indeed, both the OED and the Shorter OED now warn readers that P45 is factitious, occurring only as an example of an ultra-long word.

And that’s the problem with many of the “longest word” candidates: you only ever encounter them in discussions of very long words. The 33-letter word in the title of this post, hippopotomonstrosesquipedalianism, is even more self-referential, since it’s used to describe words that are enormously long (or sesquipedalian, literally ‘a foot and a half long’).You won’t find that in any dictionary, since it’s nothing more than a flashy “stunt word.” Then again, P45 started its life as a stunt word and then managed to find its way into dictionaries, so you never know. Supercalifragilisticexpialidocious (34 letters) was a stunt word too, specifically created for a song in Mary Poppins, but the film version of the musical was popular enough that everyone got to know the word. Now it’s in a number of dictionaries, including the OED.

Image Credit: ‘Birds eye view of Eton College’ by David Loggan, published in his ‘Cantabrigia Illustrata’ of 1690; Public Domain, via Wikimedia Commons.

A stunt word with a more distinguished pedigree is the 29-letter floccinaucinihilipilification, ‘the action or habit of estimating as worthless,’ dating back to 1741. This strings together a sequence of Latin words that were taught at Eton College: flocci, nauci, nihili, pili (meaning ‘at little value’), with the -fication suffix tacked on. This is the longest word in NOAD, the Concise OED, and many other dictionaries. It’s an obsolete word and has never been more than a lexical curiosity, but politicians seem to enjoy trying to revive it: the US senators Robert Byrd, Daniel Patrick Moynihan, and Jesse Helms have all included it in their oratory. Antidisestablishmentarianism, at 28 letters (‘opposition to the disestablishment of the Church of England’) has at least been used historically in less self-conscious contexts, but it too has become limited to simply yet another example of a very long word.

So how about words that people actually use in normal speech? A common 20-letter word is uncharacteristically, and another one is internationalization (handily called “i18n” by some to avoid spelling out the 18 letters in the middle). And there are even a few words of 22 letters in length that aren’t too ostentatious: deinstitutionalization, counterrevolutionaries, and electroencephalography. Once you get beyond the 22-letter limit, though, most long words are ones you wouldn’t encounter outside of scientific literature. Very often they’re words for chemical compounds that iconically represent the structure that they name. If they’re known to a popular audience at all, they’re given shorthand labels. So we know tetrachlorodibenzoparadioxin (28 letters) as TCDD or dioxin, methylenedioxymethamphetamine (29 letters) as MDMA or ecstasy, and dichlorodiphenyltrichloroethane (31 letters) as DDT.

Biochemists can give extravagantly long names to enzymes, lipids, and the like, since the words are formed by stringing together elements representing chains of acids. That doesn’t mean the scientists will actually use these words very often, though. Looking through the Oxford English Corpus for long words, I found a 39-letter word that does seem to be used regularly in scientific literature: it’s palmitoyloleoylphosphatidylethanolamine, a lipid known more succinctly as POPE. I hereby declare this specimen to be the POPE of outrageously long words.

Featured Image Credit: ‘Newspaper, Media, Spectacles’, Photo by stevepb, CC0 Public Domain, via pixabay.

Recent Comments

  1. Barb

    It is fascinating to hear the thoughts of a professional wordsmith on the subject of long words and their legitimacy/not. If long medical terms are not found in medical literature, does that really render them illegitimate? The example of P45 sounds plausible enough, a general term to describe a general, legitimate diagnosis. I understand that dictionaries include words used in public or specialty discourse; if P45 has notoriety because of its clever origin, isn’t that enough? Or is that why it is included in OED?

    What books can you recommend that would address this sort of thing? Do wordsmith professionals have their own periodicals, and what are the titles? I really enjoy your column. Thanks, Barb

  2. Ben Zimmer

    Barb: I agree that P45 sounds like a plausible condition. But that’s because it’s been made to look plausible, taking the actual medical term “pneumonoconiosis” and stuffing it with other material (ultramicroscopic + silico + volcano). If medical folks actually used P45 to diagnose the miner’s ailment more commonly known as “pneumonoconiosis” then it would be more acceptable from a lexicographical point of view. However, as the evidence shows, it is only (and has only ever been) a stunt word.

    Sometimes stunt words do achieve a sufficient level of notoriety that lexicographers feel obliged to put them in dictionaries. But their factitious origins still need to be noted, as is the case with P45 in the OED and the Shorter OED.

    As for books and periodicals, you might want to consult this bibliography on the website of the Dictionary Society of North America. The DSNA’s own journal is called Dictionaries.

  3. […] his post, “Hippopotomonstrosesquipedalianism!”, Ben points out that a lot of the longest words are, as he puts it, “stunt words.” […]

  4. […] his post, “Hippopotomonstrosesquipedalianism!”, Ben points out that a lot of the longest words are, as he puts it, “stunt words.” […]

  5. Chris

    What about:


    It’s the scientific name for Tryptophan synthetase, which is a protein containing 267 amino acids. It contains 1,846 letters.

  6. […] his post, “Hippopotomonstrosesquipedalianism!”, Ben points out that a lot of the longest words are, as he puts it, “stunt words.” […]

  7. […] his post, “Hippopotomonstrosesquipedalianism!”, Ben points out that a lot of the longest words are, as he puts it, “stunt words.” […]

  8. […] his post, “Hippopotomonstrosesquipedalianism!”, Ben points out that a lot of the longest words are, as he puts it, “stunt words.” […]

  9. […] prepositions are resolutely “unsexy,” quite the opposite of the ostentatious stunt words I looked at last week. But you can think of them as the connecting tissue of language, quietly […]

  10. Solaria-isitude-ness

    Forget about the long words for a moment; I’m still trying to deal with “factitious” (end of third paragraph).

    It’s troubling to think that I may have used “fictitious” when “factitious” may have been more appropriate…

  11. Sam Minter

    My favorite has always been antihypersyllabicsesquipedalian. Found in a newspaper article decades ago by my father. Definitely a “stunt word” but a good one!

  12. […] Hippopotomonstrosesquipedalianism: A Word For Describing Long Words […]

  13. hi


  14. janssen

    so, what’s the longest word?

  15. Amy

    What is the point of long words? They just confuse everyone and everybody knows that, Americans especially, are too lazy to even care for long words. So, again, I ask “What’s the point?” I myself love words, but isn’t it exhausting just thinking of a word like ‘methylenedioxymethamphetamine’ or ‘Hippopotomonstrosesquipedalianism?’ Do we really need words that only mean long words? Can’t we just say “It’s a really long word that I’m thinking of but I’m not sure how to spell or pronunciate it?”

  16. pie

    what a word

  17. S. Powell

    I found the (45 LETTER WHOPPER) on a smart cube almost 4 years ago in 2004

  18. ????

    I have known about the word pnuemonoultramiscroscopicsilicovolcanoconiosis
    for about 4 years now and just found this website today

  19. acrapapapadoo

    i think that 1,846 letter word is not considered in any dictionary…

    it’s a scientific name…what do u expect… a protein w/c contains 500 amino acids can have more letters than that…

  20. blythe

    Acetylseryltyrosylserylisoleucylthreonylserylprolylserylglutaminylphenylalanylvalyl-phenylalnelleucylserylserylvalyotriptophylalanylaspartylprolylisoleucylglutamylleucyl-lencyllasparaginylvalylcysteinythreonylserylserylleucylglycllasparatinylglutaminylphe-nylalanylglutaminylthreonylglutaminylglutaninylalanylarginylthrseonylthreonylglutam-inylvalylglutaminyglutaninylphenylalanylserylghlutaminylvalyltryptophyllysylrolylphen-ylalaylprolyglutaminylserylthreonylvalylarginylphunylalanylprolylglycylaspartylvalylty-rosyllsvslvalyltyrosylargiyltyosvlasparaginylalanylvalylleusylaspartylprolylleucylisole-ucylthreonylalnylleucylleucylglycyltreonylphnylalanylaspartylthreonylarginlasparagin-ylarginylisoleucylislleucylglutammylvalylglutamylasparaginylglutaminylglutaminylsury-lprolylthreonylthreonylalanyoglutamylthreonylleucylaspartylalanylthreonylarginylargi-nylvalylaspartylaspartylalanylthreonylvalylalanylisoleucylarginylserylalanylasparagin-ylisoleucylasparaginylleucylvallasparaginylglutamylleucylvalylarginylglycylthreonylgl-ycylleucyltyrosylasparaginylglutaminylasparaginylthreonylphenylalanylglutamylseryl-methionylserylglycylleucylvalyltryptophylthreonylserylalanylprolylalanylserine- “The scientific name for the Tobacco Mosaic Virus” (1 185 letters)

    1. Methionylglutaminylarginytyrosylglutamylserylleucylphenylalanylalanylglutaminyll-eucyllysylglutamylarginyllysylglutamylglycylalanylphenylalanyvalylprolylphenylalanyl-valythreonylleucylglycylaspartylprolyglycylisoleucylglutamylglutaminylserylleucyllysyl-isoleucylaspartylthreonylleucylisoleucylglutamylalanylglycylalanylaspartylalanylleucy-lglutamylleucylglycylglycylisoleucylprolylphenylalanylserylaspartylprolylleucelalanyla-spartyglycylprolythreonylisoleucylglutamiylasparaginylalanylthreonylleucylarginylala-nylphenylalanylalanylglycylvalyltheonylprolylalanylglutaminylcysteinylphenylalanygll-utamylmethionylleucyalanylleucylisoleucylarginylglutaminyllysylhistidylprolylthreonyl-isoleucylpriIylisoleucylglycylleucylleucylmethionyltyrosylalanylasparaginylleucylvalyp-henylalanylasparaginyllysylgyycylisoleucylaspartylglutamylphenylalanyltyrosylalanyl-gutaminyllcysteinylglutamyllysylvalylglycylavlylaspartylserylvalylleucylvalylalanylasp-artylvalyprolylvalylglutaminylglutamyllserylalanyprolyphenylalanylarginylglutaminylal-anylalanylleucylarginylhistidylasparaginylvaylalanylprolylisoleucylphenylalanylisoleu-cylcysteinylprolylprolylaspartylalanylaspartylaspartylaspartylleucylleucylarginyglutam-inylisoleucylalanyylseryltyrosylglycylarginylglycyltyrosylthreonyltyrosylleucylleucylser-ylarginylalanylglycylvalythreonylglycylalanylglutamylasparaginylarginylanylalanylleu-cylprolylleucylaspaaginylhistidylleucylvaylalanyllysylleucyllysylglutamyltyrosylasarag-inylglycylphenylalanylglycylisoleucylalanylprolylaspartylglutaminylvalyllysylalanylala-nylisoleucylaspartylalanylalanyglycylalanylalanyglycylalanylisoleucylserylglycyseryla-lanylisoleucylbalyllsylisoleucylisoleucylglutamyyylglutaminylhistidylasparaginylisole-ucylglutamylprolyglutamyllysylmethionylleucylalanylalanylleucyllysylvalylphenylalaby-lvalylglutaminlylprolylmethionyllysylalanylalanylthreonylarginylserine – “Scientific name for Trypthophan synthetase (that is a protien with 267 amino acids) (1 909 letters)

    ** – deoxyribonucleic acid (DNA) is alleged to have 207 000 letters, but has never been printed in full.

  21. jimmy de guzman

    how about the phobia word about fear on longest word that i been thinking which co0mposed atleast 39 letters.

  22. Dani

    alright i just spent 2 hours looking for the full name for deoxyribonucleic acid (DNA)it should have 207 000 letters, but its never been printed in full. so can one of you be the first to type it out and let me know how to spell it.

  23. pierre gill

    your soo mad how do you say that long word

    im choking trying to say it !!!

    i take it that it is not for novices lol

  24. Hannah

    The fear of long words is hippopotomonstrosesquipedliophobia. The love of long words or having to do with long words is called hippopotomonstrosesquipedalianism. I just love weird things like long words and the neverending number of pi. I have memorized 75 digits of pi. 3.141592653589793238462643383279502884197169399375105820974944592307816406286…
    Teehee :-) (I’m 12 years old and memorizing all that took me like 4 months. I’m gooood…)
    I wanna see the name of DNA that’s supposed to have 207 000 letters

  25. annabelle

    this is a huge word i can`t even say it. what does it mean?

  26. Dallas Brown

    What about this word,


    The adverb (34 letters)!

  27. […] In a similar vein, Ben Zimmer was able to promote our dictionaries program with a post about “long words,” which explained history, etymology, etc. Language bloggers reposted it across the Web, and a […]

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