What is the longest word in English?

  • Are you talking about the longest word in terms of letters, or longest word in terms of syllables? – Kosmonaut Nov 24 '10 at 14:26
  • The longest word in terms of number of letters. – user1784 Nov 24 '10 at 14:27
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    C'mon, we all know its supercalifragilisticexpialidocious – bobobobo Dec 21 '10 at 21:32
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    One of the bitterest disappointments of my life as a reader was when a BBC article about attempts to sever the traditional nexus between the British government and the Church of England concluded with the following, omitting (and this was the embittering part) the last word: "The Church of England will always be a part of the public life of Britain," the Archbishop's spokesperson said antidistestablishmentarianistically. – Malvolio Feb 24 '11 at 3:21

Pneumonoultramicroscopicsilicovolcanoconiosis takes the prize, I believe. It's a miner's lung disease. Outside of a doctor's office in a coal-mining community, however, one tends to hear it only when people are discussing the longest word in the English language — perhaps only slightly less often than one hears antidisestablishmentarianism.

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    Reference: en.wikipedia.org/wiki/Longest_word_in_English (there are two longer words ahead of Robusto's suggestion in the list, but their official status as words is debatable) – Kosmonaut Nov 24 '10 at 14:29
  • @Kosmonaut: My dictionary lists the "k" version as a variant spelling. It's how I learned the word back in 5th grade, when such things as the longest word in the dictionary were very important to me. But perhaps pneumanoultramicroscopicsilicovolcanoconiosis has taken over now. – Robusto Nov 24 '10 at 14:31
  • Antidisestablishmentarianism is a significantly more significant (natch) word, IMHO...it refers to the opposition of the dissolution of the Anglican church (or by extension any church) as a state entity. If an Egyptian opposes the dissolution of Sharia law as a government policy, for example, they are an antidisestablishmentarian. – Chris B. Behrens Feb 9 '11 at 16:43
  • Pneumonoultramicroscopicsilicovolcanoconiosis was specifically coined to be the longest word in English language. Does that count then? – Ankur Banerjee Apr 4 '11 at 10:29

Longest Words

(45) PNEUMONO­ULTRA­MICRO­SCOPIC­SILICO­VOLCANO­CONIOSIS (also spelled PNEUMONO­ULTRA­MICRO­SCOPIC­SILICO­VOLCANO­KONIOSIS) = a lung disease caused by breathing in particles of siliceous volcanic dust. This is the longest word in any English dictionary. However, it was coined by Everett Smith, the President of The National Puzzlers' League, in 1935 purely for the purpose of inventing a new "longest word". The Oxford English Dictionary described the word as factitious. Nevertheless it also appears in the Webster's, Random House, and Chambers dictionaries.

(37) HEPATICO­CHOLANGIO­CHOLECYST­ENTERO­STOMIES = a surgical creation of a connection between the gall bladder and a hepatic duct and between the intestine and the gall bladder. This is the longest word in Gould's Medical Dictionary.

(34) SUPER­CALI­FRAGI­LISTIC­EXPI­ALI­DOCIOUS = song title from the Walt Disney movie Mary Poppins. It is mentioned in the Oxford English Dictionary.

"But then one day I learned a word
That saved me achin' nose,
The biggest word you ever 'eard,
And this is 'ow it goes:

(30) HIPPOPOTO­MONSTRO­SESQUIPED­AL­IAN = pertaining to a very long word. From Mrs. Byrne's Dictionary of Unusual, Obscure and Preposterous Words.

(29) FLOCCI­NAUCINI­HILIPIL­IFICATION = an estimation of something as worthless. This is the longest word in the first edition of the Oxford English Dictionary. Interestingly the most common letter in English, E, does not appear in this word at all, whilst I occurs a total of nine times. The word dates back to 1741. The 1992 Guinness Book of World Records calls flocci­nauci­nihili­pilification the longest real word in the Oxford English Dictionary, and refers to pneumono­ultra­micro­scopic­silico­volcano­koniosis as the longest made-up one.

(28) ANTI­DIS­ESTABLISH­MENT­ARIAN­ISM = the belief which opposes removing the tie between church and state. Probably the most popular of the "longest words" in recent decades.

(27) HONORI­FICABILI­TUDINI­TATIBUS = honorableness. The word first appeared in English in 1599, and in 1721 was listed by Bailey's Dictionary as the longest word in English. It was used by Shakespeare in Love's Labor's Lost (Costard; Act V, Scene I):

"O, they have lived long on the alms-basket of words.
I marvel thy master hath not eaten thee for a word;
for thou art not so long by the head as
honorificabilitudinitatibus: thou art easier
swallowed than a flap-dragon."

Shakespeare does not use any other words over 17 letters in length.

(27) ELECTRO­ENCEPHALO­GRAPHICALLY The longest unhyphenated word in Merriam-Webster's Collegiate Dictionary (10th Ed.), joint with ethylene­diamine­tetraacetate (see below).

(27) ANTI­TRANSUB­STAN­TIA­TION­ALIST = one who doubts that consecrated bread and wine actually change into the body and blood of Christ.

(21) DIS­PRO­PORTION­ABLE­NESS and (21) IN­COM­PREHEN­SIB­ILITIES These are described by the 1992 Guinness Book of World Records as the longest words in common usage.

Some say SMILES is the longest word because there is a MILE between the first and last letters! :D

Chemical Terms

Two chemical terms (3,641 and 1,913 letters long) have appeared in the Guinness Book of World Records. They were withdrawn because they have never been used by chemists, and there is no theoretical limit to the length of possible legitimate chemical terms. A DNA molecule could have a name of over 1,000,000,000 letters if it was written out in full.


(39) TETRA­METHYL­DIAMINO­BENZHYDRYL­PHOSPHINOUS = a type of acid. This is the longest chemical term in the Oxford English Dictionary (2nd Ed.). It does not have its own entry but appears under a citation for another word.

(37) FORMALDEHYDE­TETRA­METHYL­AMIDO­FLUORIMUM Chemical term in the Oxford English Dictionary (2nd Ed.).

(37) DIMETHYL­AMIDO­PHENYL­DIMETHYL­PYRAZOLONE Chemical term in the Oxford English Dictionary (2nd Ed.).

(31) DICHLORO­DIPHENYL­TRICHLORO­ETHANE = a pesticide used to kill lice; abbrv. DDT. It is the longest word in the Macquarie Dictionary and is also in the Oxford English Dictionary (2nd Ed.).

(29) TRINITRO­PHENYL­METHYL­NITRAMINE = a type of explosive. This is the longest chemical term in Webster's Dictionary (3rd Ed.).

(27) ETHYLENE­DIAMINE­TETRA­ACETATE The longest unhyphenated word in Merriam-Webster's Collegiate Dictionary (10th Ed.), joint with electroencephalographically (see above).

(26) ETHYLENE­DIAMINE­TETRA­ACETIC = a type of acid; abbrv. EDTA. This word appears in Merriam-Webster's Collegiate Dictionary (10th Ed.).

Place Names

There are many long place names around the world. Here are a few of the largest.

(85) TAUMATA­WHAKA­TANGI­HANGA­KOAUAU­O­TAMATEA­TURIPUKAKA­PIKI­MAUNGA­HORO­NUKU­POKAI­WHENUA­KITANA­TAHU A hill in New Zealand. This Maori name was in general use, but is now generally abbreviated to Taumata. The name means: the summit of the hill, where Tamatea, who is known as the land eater, slid down, climbed up and swallowed mountains, played on his nose flute to his loved one.

(66) GORSA­FAWDDACH­AIDRAIGODAN­HEDDO­GLEDDOLON­PENRHYN­AREUR­DRAETH­CEREDIGION A town in Wales. The name means: the Mawddach station and its dragon teeth at the Northern Penrhyn Road on the golden beach of Cardigan bay.

(58) LLAN­FAIR­PWLL­GWYN­GYLL­GOGERY­CHWYRN­DROBWLL­LLANTY­SILIO­GOGO­GOCH A town in North Wales. The name roughly translates as: St. Mary's Church in the hollow of the white hazel near to the rapid whirlpool of Llantysilio of the red cave. It is listed in the Guinness Book of World Records.


(23) NUNATH­LOOGAGA­MIUT­BINGOI The Eskimo name for some dunes in Alaska, according to The Book of Names by J. N. Hook.

Reference: Longest Words

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    If smiles has a mile between the s's, perhaps beleaguered has a league between "be" and "red"! – Joe Z. Jan 17 '13 at 14:06

That depends on what you consider to constitute a "word" - Robusto's answer of Pneumonoultramicroscopicsilicovolcanoconiosis would be the one usually given.

There are chemical names that far exceed this (the full name for Titin, for example, would be 189,819 characters long.) However, these are generally not considered to be genuine "words" in the sense of vocabulary.