a nonmetallic element existing in the three crystalline forms: graphite, diamond, and buckminsterfullerene: occurring in carbon dioxide, coal, oil, and all organic compounds. The isotope carbon-12 has been adopted as the standard for atomic weight; carbon-14, a radioisotope with a half-life of 5700 years, is used in radiocarbon dating and as a tracer. Symbol: C; atomic no: 6; atomic wt: 12.011; valency: 2, 3, or 4; relative density: 1.8–2.1 (amorphous), 1.9–2.3 (graphite), 3.15–3.53 (diamond); sublimes at 3367±25°C; boiling pt: 4827°C (as modifier): a carbon compound - short for carbon paper, carbon copy
a carbon electrode used in a carbon-arc light or in carbon-arc welding a rod or plate, made of carbon, used in some types of battery
WordReference Random House Learner's Dictionary of American English © 2026
car•bon /ˈkɑrbən/USA pronunciation
n.
WordReference Random House Unabridged Dictionary of American English © 2026- Chemistry[uncountable] an element combined with other elements in all organic matter, and found in a pure form as diamond and graphite.
- [countable] a sheet of paper with writing or other marks copied onto it by the use of carbon paper.
- [countable] a sheet of carbon paper.
car•bon
(kär′bən),USA pronunciation n.
car′bon•less, adj.
- Chemistrya 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. - See carbon copy.
- a sheet of carbon paper.
- Electricity
- the carbon rod through which current is conducted between the electrode holder and the arc in carbon arc lighting or welding.
- the rod or plate, composed in part of carbon, used in batteries.
- French carbone, coinage based on Latin carbōn- (stem of carbō) charcoal
- 1780–90
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