Really Long Words

PNEUMONOULTRAMICROSCOPICSILICOVOLCANOCONIOSIS (45 letters; a lung disease caused by breathing in certain particles) is the longest word in any English-language dictionary. (It is also spelled -koniosis.)

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

SUPERCALIFRAGILISTICEXPIALIDOCIOUS (34 letters) from the movie Mary Poppins is not the longest word in English, although many people believe it is. The word is in the OED, which has the following as the first four citations:

1949 Parker & Young (unpublished song-title) Supercalafajalistickespialadojus.

1951 Parker & Young (song-title) Supercalafajalistickespeealadojus; or, The super song.

1964 R. M. & R. B; Sherman (song-title) Supercalifragilisticexpialidocious!

1967 Decisions U.S. Courts involving Copyright 1965-66 488 The complaint alleges copyright infringement of plaintiff's song `Supercalafajalistickespeealadojus' by defendants' song

'Supercalifragilisticexpialidocious.' (All variants of this tongue twister will hereinafter be referred to collectively as 'the word'.)

FLOCCINAUCINIHILIPILIFICATION (29 letters; an estimation of something as worthless) is the longest word in the first edition of the Oxford English Dictionary. In this word the letter i occurs nine times, but e, the most commonly used letter in English, does not occur.

TRINITROPHENYLMETHYLNITRAMINE (29 letters; a type of explosive) is the longest chemical term in W3.

ANTIDISESTABLISHMENTARIANISM (28 letters) may be the best-known long word. The word means "the belief which opposes removing the tie between church and state."