Pronunciation: (kär'bun),[key] —n. 1. Chem.a widely distributed element that forms organic compounds in combination with hydrogen, oxygen, etc., and that occurs in a pure state as diamond and graphite, and in an impure state as charcoal. Symbol: C; at. wt.: 12.011; at. no.: 6; sp. gr.: (of diamond) 3.51 at 20°C; (of graphite) 2.26 at 20°C.
2. See carbon copy. 3. a sheet of carbon paper.
4. Elect. a. the carbon rod through which current is conducted between the electrode holder and the arc in carbon arc lighting or welding.
b. the rod or plate, composed in part of carbon, used in batteries.