What is the longest ever word?

Pneumonoultramicroscopicsilicovolcanoconiosis is, according to the Oxford English Dictionary, "a factitious word alleged to mean 'a lung disease caused by the inhalation of very fine silica dust, causing inflammation in the lungs.'" A condition meeting the word's definition is normally called silicosis. It occurs chiefly as an instance of a very long word. The 45-letter word was coined to serve as the longest English word and is the longest word ever to appear in an English language dictionary. It is listed in the current edition of several dictionaries.

Lopado­temacho­selacho­galeo­kranio­leipsano­drim­hypo­trimmato­silphi o­parao­melito­katakechy­meno­kichl­epi­kossypho­phatto­perister­alekt ryon­opte­kephallio­kigklo­peleio­lagoio­siraio­baphe­tragano­pterygon is a fictional dish mentioned in Aristophanes' comedy Assemblywomen. The original Greek spelling had 171 characters (something which is not obvious in the Roman transcription, depending on the variant) and for centuries it was the longest word known.

Heres another word that is supposed to be the largest. Believe it or not the world’s longest word has around 189,819 letters within it, this word has only 49 letters. If you guys were wondering what the world’s longest word is, I am sorry I couldn’t write the whole word because it’s too big…

Methionylthreonylthreonylglutaminylarginyl…isoleucine

Did you know that the world’s longest word is the chemical word for titin, a five letter word!

There are those who claim that "smiles" is the longest word, because there's a mile between the first and last letter!