The noun Pneumonoultramicroscopicsilicovolcanoconiosis (Noo-muh-noh ul-truh my-kruh-skop-ik sil-i-koh vol-kay-no koh-nee-oh-sis) is a 45-letter word recognized as the longest word in major English dictionaries. It was invented by Everett K. Smith in 1935 as a linguistic "trophy word" to serve as a synonym for silicosis, which is a severe and often fatal lung disease.
