A lung disease caused by breathing in particles of siliceous volcanic dust: During the recovery efforts after the eruption of the volcano, the rescue worker was hospitalized with a diagnosis of pneumonoultramicroscopicsilicovolcanokoniosis and the doctors were uncertain as to how to treat it.

This is considered to be the longest word in any English dictionary; however, it was coined by Everett Smith, the President of The National Puzzlers' League, in 1935 purely for the purpose of inventing a new "longest word".

The Oxford English Dictionary described the word as factitious; however, it also appears in the Webster's, Random House, and Chambers dictionaries.

Much shorter words already existed to describe such conditions; for example, "pneumoconiosis" (noo" moh koh" nee OH sis), or "Miner's Lung", which is the term for a lung condition in which inhalation of dust leads to the formation of lumps of fibrous tissue in the lungs, and "silicosis", or "Grinder's Disease", that is the term for such a condition when caused by crystalline silica dust.