n. 1 a a usu. large musical instrument having pipes supplied with air from bellows, sounded by keys, and distributed into sets or stops which form partial organs, each with a separate keyboard (choir organ; pedal organ). b a smaller instrument without pipes, producing similar sounds electronically. c a smaller keyboard wind instrument with metal reeds; a harmonium. d = barrel-organ. 2 a a usu. self-contained part of an organism having a special vital function (vocal organs; digestive organs). b esp. joc. the penis. 3 a medium of communication, esp. a newspaper, sectarian periodical, etc. 4 archaic a professionally trained singing voice. 5 Phrenol. archaic a region of the brain held to be the seat of a particular faculty. organ-blower a person or mechanism working the bellows of an organ. organ-grinder the player of a barrel-organ. organ-loft a gallery in a church or concert-room for an organ. organ of Corti see CORTI. organ-pipe any of the pipes on an organ. organ-screen an ornamental screen usu. between the choir and the nave of a church, cathedral, etc., on which the organ is placed. organ-stop 1 a set of pipes of a similar tone in an organ. 2 the handle of the mechanism that brings it into action.
[ ME f. OE organa & OF organe, f. L organum f. Gk organon tool ]