Longest English word...

acetylseryltyrosylserylisoleucylthreonylserylprolylserylglutaminyl
phenylalanylvalylphenylalanylleucylserylserylvalyltryptophylalanyl
aspartylprolylisoleucylglutamylleucylleucylasparaginylvalylcysteinyl
threonylserylserylleucylglycylasparaginylglutaminylphenylalanyl
glutaminylthreonylglutaminylglutaminylalanylarginylthreonylthreonyl
glutaminylvalylglutaminylglutaminylphenylalanylserylglutaminylvalyl
tryptophyllysylprolylphenylalanylprolylglutaminylserylthreonylvalyl
arginylphenylalanylprolylglycylaspartylvalyltyrosyllysylvalyltyrosyl
arginyltyrosylasparaginylalanylvalylleucylaspartylprolylleucylisoleucyl
threonylalanylleucylleucylglycylthreonylphenylalanylaspartylthreonyl
arginylasparaginylarginylisoleucylisoleucylglutamylvalylglutamyl
asparaginylglutaminylglutaminylserylprolylthreonylthreonylalanylglutamyl
threonylleucylaspartylalanylthreonylarginylarginylvalylaspartylaspartyl
alanylthreonylvalylalanylisoleucylarginylserylalanylasparaginylisoleucyl
asparaginylleucylvalylasparaginylglutamylleucylvalylarginylglycyl
threonylglycylleucyltyrosylasparaginylglutaminylasparaginylthreonyl
phenylalanylglutamylserylmethionylserylglycylleucylvalyltryptophyl
threonylserylalanylprolylalanylserine
it means- This 1185-letter "word" is the chemical name for "Coat Protein, Tobacco Mosaic Virus, Dahlemense Strain". The term was published in the American Chemical Society's Chemical Abstracts in 1972, and is considered by some to be the longest real word. It does hold the record for the longest word in an English language publication in a serious context, that is, for some reason other than to publish a very long word.