an instrument or medium by which some important action is performed, or an important end accomplished; as, legislatures, courts, armies, taxgatherers, etc., are organs of government.-a natural part or structure in an animal or a plant, capable of performing some special action (termed its function), which is essential to the life or well-being of the whole; as, the heart, lungs, etc., are organs of animals; the root, stem, foliage, etc., are organs of plants.-a component part performing an essential office in the working of any complex machine; as, the cylinder, valves, crank, etc., are organs of the steam engine.-a medium of communication between one person or body and another; as, the secretary of state is the organ of communication between the government and a foreign power; a newspaper is the organ of its editor, or of a party, sect, etc.-a wind instrument containing numerous pipes of various dimensions and kinds, which are filled with wind from a bellows, and played upon by means of keys similar to those of a piano, and sometimes by foot keys or pedals; -- formerly used in the plural, each pipe being considired an organ.-to supply with an organ or organs; to fit with organs; to organize.