Methionylthreonylthreonylglutaminylarginyl...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	Longest published word[1]	Technical
Lopadotemachoselachogaleokranioleipsano...pterygon	183	Longest word coined by a major author,[2] the longest word ever to appear in literature.[3]	Coined; not in dictionary; Ancient Greek transliteration
Pneumonoultramicroscopicsilicovolcanoconiosis	45	Longest word in a major dictionary[4]	Technical; coined to be the longest word
Supercalifragilisticexpialidocious	34	Famous for being created for the Mary Poppins film and musical	Coined
Pseudopseudohypoparathyroidism	30	Longest non-coined word in a major dictionary[5]	Technical
Floccinaucinihilipilification	29	Longest unchallenged nontechnical word	Coined
Antidisestablishmentarianism	28	Longest non-coined and nontechnical word[6]
Honorificabilitudinitatibus	27	Longest word in Shakespeare's works; longest word in the English language featuring alternating consonants and vowels.[7]	Latin