jockey [L16th] A pet form of the man’s name Jock, a northern form of *jack, jockey was originally used, rather like Jack, for any ordinary man, boy, or underling. From this came a specialized sense of a servant as a mounted courier, which in the 17th century gave rise to today’s meaning. In American slang a jockey was a specific kind of worker—so a beer jockey was a barmaid, a garage jockey a garage attendant, and a typewriter jockey a typist. From there it was natural to call someone who played records a disc jockey, in the 1940s.