barrel organ

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A mechanical instrument on which a tune is played by the action of a revolving cylinder fitted with pegs or pins that open pipe valves supplied by a bellows.

from The Century Dictionary.

• noun An organ with a cylinder or barrel turned by a crank and furnished with pegs or staples, which, when the barrel revolves, open a series of valves admitting currents of air from a bellows actuated by the same motion to a set of pipes, thus producing a tune either in melody or in harmony.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A musical instrument in which air from a bellows is admitted to a set of pipes by means of pins inserted into a revolving barrel.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a musical instrument that makes music by rotation of a cylinder studded with pegs