The longest English word is pneumonoultramicroscopicsilicovolcanoconiosis (43 letters),
which is a disease caused by a prolonged exposure to fine siliceous
The second, third, and forth longest words are as follows:
While pneumonoultramicroscopicsilicovolcanoconiosis is the
longest word you can find in the English dictionary, some people
disagree that it is truly the longest English word. For instance,
chemists occasionally use molecule names with many more letters.
While you will not find these long chemical names in the dictionary,
they are valid scientific terms, which represent the structure of a
complex molecule by a very long compound word. The longest of chemical
contains 189,819 letters. This monster word descibes the strucutre of
titin, which is the
largest known protein.
(30 letters): An inherited disorder that closely simulates the
symptoms but not the consequences of pseudohypoparathyroidism; thus, it
has mild or no manifestations of hypoparathyroidism.
(29 letters): An act of describing something as worthless, or making
something to be worthless by deprecation.
(28 letters): A political position that originated in
nineteenth-century Britain; antidisestablishmentarians were opposed to
disestablishmentarians, who argued for removing the Church of
England's status as the state church of England.
Another good candidate for the longest word is
which is the English translitiration of a fictional dish once
mentioned by Aristophanes', an Ancient Greek writer.
Finally, some people claim that the longest English word is
smiles because it has a whole mile between its first and
You may learn more about long English words from the related Wikipedia