funpics

The word pneumonoultramicroscopicsilicovolcanoconiosis (also spelled -koniosis) is defined as "a lung disease caused by the inhalation of very fine silica (sandlike) dust, mostly found in volcanoes". It was originally coined simply to serve as the longest English word, but has been used in several sources as an approximation of its originally intended definition. The name generally used to describe this condition is pneumoconiosis, which is much shorter.
History
It is the longest word ever to appear in an English language dictionary. This 45-letter word, referred to by logologists as "P45", first appeared in the Oxford English Dictionary in 1936, and has also since appeared in the Webster's Third New International Dictionary, the Random House Dictionary of the English Language, Unabridged, and Merriam-Webster's Collegiate Dictionary and Medical Dictionary.

Critics of its designation as the longest word complained that it is a technical (specifically, medical) term, and hence not worthy of consideration as the "longest word in general usage".

However, the more serious problem is that the word was originally intended as a hoax: In Word Ways: The Journal of Recreational Linguistics, in several separate articles (May 1985, pp. 95-96; November 1986, pp. 205-206; May 1987, p. 82; November 1989, p. 205 ), researchers discovered that the word was invented in 1935 by Everett M. Smith, president of the National Puzzlers' League, at their annual meeting. The word occurred in a newspaper headline about the meeting, after which it was picked up by an author of puzzle books. Members of the National Puzzlers' League then campaigned to have it included in major dictionaries, eventually succeeding with the Oxford English Dictionary and Webster's Third. Research into medical literature prior to 1935 has failed to find the word. It has since been used, albeit sparingly.
References in Popular Culture

    * It was mentioned by Abraham Simpson in the Simpsons episode Grampa vs. Sexual Inadequacy in 1994.
    * In Sonic Drive-In's Wacky Pack meal, it is mentioned on their "Smart Cube" toys.
    * It was mentioned in Jon Stewart's America (The Book)