| Word | Letters | Pros | Cons |
|---|---|---|---|
| Methionylthreonylthreonyl...isoleucine | 189,819 | Chemical name of the largest known protein | Technical; not in dictionary; disputed whether it is a word |
| Lopado...pterygon | 183 | Longest word coined by a major author | Coined; not in dictionary; Greek transliteration |
| Pneumonoultramicroscopicsilicovolcanoconiosis | 45 | Longest word in a major dictionary | Technical; coined to be the longest word |
| Pseudopseudohypoparathyroidism | 30 | Longest non-coined word in a major dictionary | Technical |
| Floccinaucinihilipilification | 29 | Longest nontechnical word | Coined |
| Antidisestablishmentarianism | 28 | Longest non-coined and nontechnical word | |
| Honorificabilitudinitatibus | 27 | Longest word in Shakespeare's works |
The longest word in any of the major English language dictionaries is pneumonoultramicroscopicsilicovolcanoconiosis, a word which refers to a lung disease contracted from the inhalation of very fine silica particles, specifically from a volcano. Research has discovered that this word was originally a hoax. It has since been used in a close approximation of its originally intended meaning, lending at least some degree of validity to its claim.
The Oxford English Dictionary contains pseudopseudohypoparathyroidism (30 letters).
The longest non-technical word in major dictionaries is floccinaucinihilipilification at 29 letters. Consisting of a series of Latin words meaning "nothing" and defined as "the act of estimating something as worthless", its usage has been recorded as far back as 1741.
Henry Carey's farce Chrononhotonthologos (1743) holds the opening line: "Aldiborontiphoscophornio! Where left you Chrononhotonthologos?"
James Joyce made up nine 101-letter words in his novel Finnegans Wake, the most famous of which is Bababadalgharaghtakamminarronnkonnbronntonnerronntuonnthunntrovarrhounawnskawntoohoohoordenenthurnuk. Appearing on the first page, it allegedly represents the symbolic thunderclap associated with the fall of Adam and Eve. As it appears nowhere else except in reference to this passage, it is generally not accepted as a real word. Sylvia Plath made mention of it in her semi-autobiographical novel The Bell Jar, when the protagonist was reading Finnegans Wake.
"Supercalifragilisticexpialidocious", the 34-letter title of a song from the movie Mary Poppins, does appear in several dictionaries, but only as a proper noun defined in reference to the song title. The attributed meaning is "a word that you say when you don't know what to say." The idea and invention of the word is credited to songwriters Robert and Richard Sherman.
"The holy Jah" is a 4.4-million-letter word in "Marienbad My Love" by Mark Leach. It is comprised of pieces of various words from the world's faiths and means "god within.
"Babyoubiquitouse...oiletub" is a 2,087,214-letter word which occupies almost all Nigel Tomm's novel The Blah Story, Volume 10 and means something like a girl or a bitch.
In 1975, the 71-letter (but several-word) advertising jingle Twoallbeefpattiesspecialsaucelettucecheesepicklesonionsonasesameseedbun (read: two all-beef patties, special sauce, lettuce, cheese, pickles, onions on a sesame seed bun) was first used in a McDonald's Restaurant advertisement to describe the Big Mac sandwich.
"Antidisestablishmentarianism" is the longest common example of a word formed by agglutinative construction, as follows (the numbers succeeding the word refer to the number of letters in the word):establish (9): to set up, put in place, or institute (originally from the Latin stare, to stand)dis-establish (12): ending the established status of a body, in particular a church, given such status by law, such as the Church of Englanddisestablish-ment (16): the separation of church and state (specifically in this context it is the political movement of the 1860s in Britain)anti-disestablishment (20): opposition to disestablishmentantidisestablishment-arian (25): an advocate of opposition to disestablishmentantidisestablishmentarian-ism (28): the movement or ideology that opposes disestablishment
The use of additional suffixes could stretch the word to 'antidisestablishmentarianisticalized,' with 36 letters. Of course, the process need not stop there: prefixes like neo- and contra- can be added.
Gammaracanthuskytodermogammarus loricatobaicalensis is sometimes cited as the longest binomial name—it is a kind of amphipod. However, this name, proposed by B. Dybowski, was invalidated by the International Code of Zoological Nomenclature.
Aequeosalinocalcalinoceraceoaluminosocupreovitriolic, at 52 letters, describing the spa waters at Bath, England, is attributed to Dr. Edward Strother (1675-1737). The word is composed of the following elements:
John Horton Conway and Landon Curt Noll developed an open-ended system for naming powers of 10, in which one sexmilliaquingentsexagintillion, coming from the Latin name for 6560, is the name for 103(6560+1) = 1019683. Under the long number scale, it would be 106(6560) = 1039360.
Names of chemical compounds can be extremely long if written as one word, as is sometimes done. An example of this is sodiummetadiaminoparadioxyarsenobenzoemethylenesulphoxylate, an arsenic-containing drug. There are also other chemical naming systems, using numbers instead of "meta", "para" etc. as descriptive dividers, breaking up the name, which then no longer can be considered a single long word. One example, with 1,185 letters, is a chemical term referring to the coat protein of a certain strain of tobacco mosaic virus.
The IUPAC nomenclature for organic chemical compounds is open-ended, giving rise to the 189,819-letter chemical name Methionylthreonylthreonyl...isoleucine, the shortened version of a protein also known as titin, or sometimes connectin, which is involved in striated muscle formation. Its empirical formula is C132983H211861N36149O40883S693.
The longest officially recognized place name in an English-speaking country is Taumatawhakatangihangakoauauotamateaturipukakapikimaungahoronukupokaiwhenuakitanatahul (85 letters) which is a hill in New Zealand.
The longest place name in the United States (45 letters) is Chargoggagoggmanchauggagoggchaubunagungamaugg, a lake in Webster, Massachusetts. It means "Englishmen at Manchaug at the Fishing Place at the Boundary" and is sometimes facetiously translated as "you fish your side of the water, I fish my side of the water, nobody fishes the middle". The lake is also known as Lake Webster. The longest hyphenated names in the U.S. are Winchester-on-the-Severn, a town in Maryland, and Washington-on-the-Brazos, a notable place in Texas history.
The 58-character name Llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch is the famous name of a town on Anglesey, an island of Wales. This place's name is actually 51 letters long, as certain character groups in Welsh are considered as one letter, for instance ll, ng and ch. It is generally agreed, however, that this invented name, adopted in the mid-19th century, was contrived solely to be the longest name of any town in Britain. The official name of the place is Llanfairpwllgwyngyll, commonly abbreviated to Llanfairpwll or the somewhat jocular Llanfair PG.
The longest official geographical name in Australia is Mamungkukumpurangkuntjunya Hill. It is a Pitjantjatjara word meaning "where the Devil urinates".
In Ireland, the longest English placename at 22 letters is Muckanaghederdauhaulia (from the Irish language, Muiceanach Idir Dhá Sháile, meaning "pig-marsh between two saltwater inlets") in County Galway. If this is disallowed for being derived from Irish, or not a town, the longest at 19 letters is Newtownmountkennedy in County Wicklow.
It is questionable whether any of the above (with the exception of Newtownmountkennedy) are properly considered English words, being derived from Maori, Nipmuck, Welsh, Aboriginal and Irish words respectively, or being a conjunction of individual English words.