The Guinness Book of Records, in its 1992 and subsequent editions, declared the "longest real word" in the English language to be floccinaucinihilipilification at 29 letters. Defined as the act of estimating as worthless, its usage has been recorded as far back as 1741.
The word pneumonoultramicroscopicsilicovolcanoconiosis, also spelled pneumonoultramicroscopicsilicovolcanokoniosis, is defined as "a lung disease caused by the inhalation of very fine silica or quartz dust." At 45 letters, it is certainly the longest word ever to appear in a non-technical dictionary of English (Source: OED). However there are strong indications that the word was coined by puzzler Everett Smith in 1935 as a hypothetical long word that could result from the protraction of medical terms. The actual name of the disease is pneumoconiosis, which is 14 letters long.



