Taumatawhakatangihangakoauauotamateapokaiwhenuakitanatahu, something like that

Antidisastablishmentarianisms

The longest in common use, according to a study, are uncharacteristically (20 letters), deinstutionalisation (22 letters) and counterrevolutionaries (22 letters). Anything longer than this is a place name, a made-up word, a rare word or a scientific word.

Have you heard of 'google'? Try this: http://lmgtfy.com/?q=longest+word+in+English

i don't remember it now. but i think its a name of one country in Aafrica o Europe...