acetylseryltyrosylserylisoleucylthreonylserylprolylserylglutaminyl- phenylalanylvalylphenylalanylleucylserylserylvalyltryptophylalanyl- aspartylprolylisoleucylglutamylleucylleucylasparaginylvalylcysteinyl- threonylserylserylleucylglycylasparaginylglutaminylphenylalanyl- glutaminylthreonylglutaminylglutaminylalanylarginylthreonylthreonyl- glutaminylvalylglutaminylglutaminylphenylalanylserylglutaminylvalyl- tryptophyllysylprolylphenylalanylprolylglutaminylserylthreonylvalyl- arginylphenylalanylprolylglycylaspartylvalyltyrosyllysylvalyltyrosyl- arginyltyrosylasparaginylalanylvalylleucylaspartylprolylleucylisoleucyl- threonylalanylleucylleucylglycylthreonylphenylalanylaspartylthreonyl- arginylasparaginylarginylisoleucylisoleucylglutamylvalylglutamyl- asparaginylglutaminylglutaminylserylprolylthreonylthreonylalanylglutamyl- threonylleucylaspartylalanylthreonylarginylarginylvalylaspartylaspartyl- alanylthreonylvalylalanylisoleucylarginylserylalanylasparaginylisoleucyl- asparaginylleucylvalylasparaginylglutamylleucylvalylarginylglycyl- threonylglycylleucyltyrosylasparaginylglutaminylasparaginylthreonyl- phenylalanylglutamylserylmethionylserylglycylleucylvalyltryptophyl- threonylserylalanylprolylalanylserine

This 1185-letter “word” is the chemical name for “Coat Protein, Tobacco Mosaic Virus, Dahlemense Strain”. It is supposedly the longest word in the English language.

The name on the sign that marks this hill is ‘Taumatawhakatangihangakoauauotamateaturipukakapikimaungahoronukupokaiwhenuakitanatahu’, which translates roughly as The summit where Tamatea, the man with the big knees, the climber of mountains, the land-swallower who travelled about, played his flute to his loved one. At 85 letters, it is one of the longest placenames in the world.

Pneumonoultramicroscopicsilicovolcanoconiosis, 45 letters, longest word in any of the major English language dictionaries including the OED

pneumonoultramicroscopicsilicovolcanoconiosis – a 45-letter word which refers to a lung disease contracted from the inhalation of very fine silicious particles