Longest word in English
The identity of the longest word in English depends upon the definition of what constitutes a word in the English language, as well as how length should be compared.

Longest word in English

Section Title:
Table Section Text: The identity of the longest word in English depends upon the definition of what constitutes a word in the English language, as well as how length should be compared.

Word	Letters	Characteristics	Dispute

Methionylthreonylthreonylglutaminylalanyl...isoleucine	189,819	Chemical name of titin, the largest known protein	Technical; not in dictionary; disputed whether it is a word

Methionylglutaminylarginyltyrosylglutamyl...serine	1,909	Chemical name of E. coli TrpA (P0A877); longest published word	Technical

Lopadotemachoselachogaleokranioleipsano...pterygon	182	Longest word coined by a major author, the longest word ever to appear in literature	Coined; not in dictionary; Ancient Greek transliteration

Pneumonoultramicroscopicsilicovolcanoconiosis	45	Longest word in a major dictionary	Technical; coined to be the longest word

Supercalifragilisticexpialidocious	34	Made popular in the Mary Poppins film and musical	Coined

Pseudopseudohypoparathyroidism	30	Longest non-coined word in a major dictionary	Technical

Floccinaucinihilipilification	29	Longest unchallenged nontechnical word	Coined

Antidisestablishmentarianism	28	Longest non-coined and nontechnical word	Not all dictionaries accept it due to lack of usage.

Honorificabilitudinitatibus	27	Longest word in Shakespeare's works; longest word in the English language featuring alternating consonants and vowels	Latin

Sentence(s)

Longest word in English with a 1909-letter word describing the trpA (P0A877).

final_sentence: Longest word in English with a 1909-letter word describing the trpA (P0A877).