late 13c., "a part of a body where two bones meet and move in contact with one another," from O.Fr. joint, from L. junctus, pp. of jungere "join" (see jugular
). Slang meaning of "place, building, establishment" (esp. one where persons meet for shady activities) first recorded
1877, Amer.Eng., from an earlier Anglo-Irish sense (1821), perhaps on the notion of a side-room, one "joined" to a main room. The original U.S. sense was especially of "an opium-smoking den." Meaning "marijuana cigarette" (1938) is perhaps from notion of something often smoked in common, but there are other possibilities; earlier joint in drug slang meant "hypodermic outfit" (1935). Meaning "prison" is from 1953.