Pneumonoultramicroscopicsilicovolcanoconiosis is, according to the Oxford English Dictionary, "a word invented in imitation of polysyllabic medical terms, alleged to mean ‘a lung disease caused by the inhalation of very fine sand and ash dust (mostly volcanic silica ash dust)’ but occurring only as an instance of a very long word."Oxford English Dictionary; Pneumonoultramicroscopicsilicovolcanoconiosis definition in the Oxford English Dictionary A condition meeting the word's definition is normally called silicosis.