"People sometimes ask whether a DNA string can be considered as the longest English word, given that they can run to many thousands of letters. The answer is no: they're regarded as chemical names rather than genuine words in the sense of meaningful items of vocabulary"
-Oxford Dictionaries
The longest word in the Oxford dictionary is pneumonoultramicroscopicsilicovolcanoconiosis. It is 45 letters long.
I can't spell it yet, but I can pronounce it correctly.
