aequeosalinocalcalinosetaceoaluminosocupreovitriolic
(52 letters; a word coined by 16th century medical writer Edward Strother to describe the spa waters at Bath.)

chargoggagoggmanchauggagoggchaubunagungamaugg
(45 letters long; America's longest place name, it refers to a lake near Webster, Massachusetts. Translation: "You fish on the left side, I'll fish on the right side, no one fishes in the middle.")

cholangiocholecystocholedochectomy
(34 letters; a cutting out of the hepatic duct, common bile duct, and gall bladder. Yummy.)

floccinaucinihilipilification
(29 letters, the categorizing of something as worthless trivia.)

gynotikolobomassophile
(22 letters; one who likes to nibble on a woman's earlobe)

llanfairpwllgwyngyllgogerychwyrndrobwllllantysiliogogogoch
(58 letters long; the place in Gwynedd, North Wales, famed for its railway ticket lengths--duh! Translation: "St. Mary's Church in the hollow of the white hazel near to the rapid whirlpool of Llantysilio of the Red Cave.")

lopadotemachoselachogaleokranioleipsanodrimhypotrimmatosilphioparaomelitokatakechymenokichlepikossyphophattoperisteralektryonoptekephalliokigklopeleiolagoiosiraiobaphetraganopterygon
(189 letters; a ghoulash composed of all the leftovers from the meals of the leftovers from the meals of the last two weeks--from Aristophanes' The Ecclesiaszusae)

pneumonoultramicroscopicsilicovolcanoconiosis
(45 letters long; refers to a lung disease resulting from breathing very fine dust) .

pseudoantidisestablishmentarianism
(34 letters; refers to "false opposition to the withdrawal of state support from a Church.")

supercalifragilisticexpialidocious
(34 letters; easily the most obscure word on this page, it means "atoning for extreme and delicate beauty while highly educable")