a common metal of a reddish color, both ductile and malleable, and very tenacious. it is one of the best conductors of heat and electricity. symbol cu. atomic weight 63.3. it is one of the most useful metals in itself, and also in its alloys, brass and bronze.-a coin made of copper; a penny, cent, or other minor coin of copper.-a vessel, especially a large boiler, made of copper.-the boilers in the galley for cooking; as, a ship's coppers.-to cover or coat with copper; to sheathe with sheets of copper; as, to copper a ship.