OR'GAN, noun [Latin organum; Gr.]

1. A natural instrument of action or operation, or by which some process is carried on. Thus the arteries and veins of animal bodies are organs of circulation; the lungs are organs of respiration; the nerves are organs of perception and sensation; the muscles are organs of motion; the ears are organs of hearing; the tongue is the organ of speech.

2. The instrument or means of conveyance or communication. A secretary of state is the organ of communication between the government and a foreign power.

3. The largest and most harmonious of wind instruments of music, consisting of pipes which are filled with wind, and stops touched by the fingers. It is blown by a bellows.