carbon

(noun) an abundant nonmetallic tetravalent element occurring in three allotropic forms: amorphous carbon and graphite and diamond; occurs in all organic compounds. Synonyms: C, atomic number 6.

(noun) 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. Synonyms: carbon paper.

(noun) a copy made with carbon paper. Synonyms: carbon copy.