Find It! Pneumonoultramicroscopicsilicovolcanoconiosis - In major dictionaries. 45 letters. Lopado*temakho*selakho*galeo*kranio*leipsano*drim*hypo*trimmato*silphio*karabo*melito*katakekhy*meno*kikhl*epi*kossypho*phatto*perister*alektryon*opto*kephallio*kigklo*peleio*lagōio*siraio*baphē*tragano*pterýgōn - Longest word used by a major author, Aristophanes. 183 letters. And the biggest, a whopping 189819 letters long, the chemical name for Titin. http://luminaryuprise.wikidot.com/longest-word I think I win!
Supercalifragilisticexpialidocious Lopado*temakho*selakho*galeo*kranio*leipsano*drim*hypo*trimmato*silphio*karabo*melito*katakekhy*meno*kikhl*epi*kossypho*phatto*perister*alektryon*opto*kephallio*kigklo*peleio*lagōio*siraio*baphē*tragano*pterýgōn Yes it is a word Someone had to say it!
กรุงเทพมหานครอมรรัตนโกสินทร์มหินทรายุธยามหาดิลกภพนพรัตน์ราชธานีบุรีรมย์อุดมราชนิเวศน์มหาสถานอมรพิมานอวตารสถิตสักกทัตติยะวิษณุกรรมประสิทธิ์ Which in Roman letters is Krung Thep Mahanakhon Amon Rattanakosin Mahinthara Ayuthaya Mahadilok Phop Noppharat Ratchathani Burirom Udomratchaniwet Mahasathan Amon Piman Awatan Sathit Sakkathattiya Witsanukam Prasit Which means The city of angels, the great city, the residence of the Emerald Buddha, the impregnable city (of Ayutthaya) of God Indra, the grand capital of the world endowed with nine precious gems, the happy city, abounding in an enormous Royal Palace that resembles the heavenly abode where reigns the reincarnated god, a city given by Indra and built by Vishnukarn. EDIT: Damn autospacing
Longest nontechnical word in the Oxford English Dictionary is floccinaucinihilipilification, which means "the action or habit of estimating something as worthless." More long words that are either technical, coined, both, or neither: http://en.wikipedia.org/wiki/Longest_word_in_English Of course, even titin doesn't win: the technical name for one DNA molecule in a human chromosome 1 would have billions of letters, since chromosome 1 has about 220,000,000 base pairs. Since DNA is actually two molecules tightly bound, the name would apply to half of a strand. The fact that this word hasn't been written out as far as I know is the only reason titin could still be considered.