Mental Floss

12 of the Longest Words in the World, By Category

Kevin Kampwirth
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Antidisestablishmentarianism, everyone’s favorite agglutinative, entered the pop culture lexicon on August 17, 1955, when Gloria Lockerman, a 12-year-old girl from Baltimore, correctly spelled it on The $64,000 Question as millions of people watched from their living rooms. At 28 letters, the word—which is defined as a 19th-century British political movement that opposes proposals for the disestablishment of the Church of England—is still regarded as the longest non-medical, non-coined, nontechnical word in the English language (though according to Merriam-Webster, it’s rarely used outside of being "a really long word"). And it keeps some robust company. Here are some examples of the longest words by category.

1. Methionylthreonylthreonyglutaminylarginyl ... isoleucine

Note the ellipses. All told, the full chemical name for the human protein titin is 189,819 letters, and takes up to three-and-a-half hours to pronounce. The problem with including chemical names is that there’s essentially no limit to how long they can be. For example, naming a single molecule of DNA, with its millions and millions of repeating base pairs, could eventually tap out at well over 1 billion letters.

2. Nirantarāndhakāritā … lokān

According to Guinness World Records, the longest word in any language is a "compound 'word' of 195 Sanskrit characters (transliterating to 428 letters in the Roman alphabet) describing the region near Kanci, Tamil Nadu, India, which appears in a 16th-century work by Tirumalãmbã, Queen of Vijayangara.”

3. Pneumonoultramicroscopicsilicovolcanoconiosis

At 45 letters, this is the longest defined word you’ll find in a major dictionary. An inflated version of silicosis, this is the vaguely scientific-sounding name for a disease that causes inflammation in the lungs owing to the inhalation of very fine silica dust. Despite its inclusion in the dictionary, it’s generally considered superfluous, having been coined simply to claim the title of the longest English word.

While pneumonoultramicroscopicsilicovolcanoconiosis is often given as the longest word in a dictionary, it’s not that straightforward. As explained in a 1997 article by Darryl Francis in the journal Word Ways, dictionaries—especially the Oxford English Dictionary—have the defined words but also quotations to show usage. So the first entry under hamburger, for example, contains a 55-letter word, with nary a space in sight: “You are asked if you will have ‘porkchopbeefsteakhamandegghamburgersteakorliverandbacon.’” Allowing for any non-space punctuation, under the word journey there’s this behemoth from 1938: “feeling-upset-physically-and-mentally-with-anticipatory-excitement-and/or-anxiety”—71 letters (and some hyphens and a slash; but no spaces). Francis even points out that there’s a 100-character “word” hiding under lincomycin, but that’s a chemical name. The longest word in the dictionary is, therefore, somewhat open to interpretation.

4. Parastratiosphecomyia Stratioshecomyioides

The longest accepted animal binomial, at 42 letters, is a species of soldier fly native to Thailand. The name dwarfs the creature, which has a length of just over 10 millimeters.

5. Pseudopseudohypoparathyroidism

This 30-letter medical condition is the longest non-coined word to appear in a major dictionary.

6. Floccinaucinihilipilification

By virtue of having one more letter than antidisestablishmentarianism, this is the longest non-technical English word. A mash-up of five Latin elements, it refers to the act of describing something as having little or no value. While it made the cut in the Oxford English Dictionary, Merriam-Webster volumes refuse to recognize it, chalking up its existence to little more than linguistic ephemera.

7. Subdermatoglyphic

At 17 characters, this is often considered the longest isogram, a word in which every letter is used only once, and refers to the underlying dermal matrix that determines the pattern formed by the whorls, arches, and ridges of our fingerprints. 

8. Squirrelled

Though the more commonly accepted American English version carries only one L, the version with two is fully accepted—and in some accents it’s pronounced as one-syllable, making it possibly the longest non-coined monosyllabic English word at 11 letters.

9. Transtendinous

Are you having a surgery that might involve going through the tendon? Then you might hear the word transtendinous thrown around. Are you at a conference of lexicographers? You might hear transtendinous thrown around as, at 14 letters, potentially the longest English word to use all five vowels in order exactly once. But as that word (and the equally 14-letter lamelligomphus, a dragonfly genus) has yet to enter the hallowed halls of the better dictionaries, you might be better off with the 12 letters of abstemiously and affectiously, both of which have a pleasing Y to round out the word (and a special shout out to uncomplimentary, which, at 15 letters, has all five—though not the Y—in reverse alphabetical order).

10. Tattarrattat

At 12 letters, this word—coined by James Joyce in Ulysses and meaning a knocking at the door—is likely the longest palindromic word in English. 

Joyce had a penchant for coining weird words that no one uses, so a better candidate for longest non-coined palindromic word in major dictionaries might be the nine-letter Malayalam, which is a Dravidian language spoken in parts of India. (A third candidate—detartrated—appears in some chemical glossaries and older food science publications, but is rarely included in dictionaries.)

11. and 12. Euouae and Psst

Euouae and psst are the longest words comprised entirely of either vowels or consonants appearing in a major dictionary. Euouae, a medieval musical term, is technically a mnemonic, but has been accepted as a word in itself.

As for longest without vowels, Guinness World Records gives the record for “Longest word in the English language without any of the five main vowels” as twyndyllyngs, the plural of an obscure 15th-century variant of an obscure now dialectical word meaning “twin.” But as American students learn, Y is sometimes a vowel.

Some argue cwtch (cupboard/hiding place or a special hug) or crwth (a type of musical instrument) hold the record, but in both of those, the W is taking the vowel role, as it can happily do in the Welsh both are loaned from. For something with neither a vowel letter nor a vowel sound, the best option is likely psst, which is a fully accepted word in the Oxford English Dictionary.

Austin Thompson contributed to this piece. A version of this story ran in 2016; it has been updated for 2022.