1. (noun)carbon, C, atomic number 6 an abundant nonmetallic tetravalent element occurring in three allotropic forms: amorphous carbon and graphite and diamond; occurs in all organic compounds
2. (noun)carbon paper, carbon a thin paper coated on one side with a dark waxy substance (often containing carbon); used to transfer characters from the original to an under sheet of paper
3. (noun)carbon, carbon copy a copy made with carbon paper