pencil lead, lead - mixture of graphite with clay in different degrees of hardness; the marking substance in a pencil

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

pencil - graphite (or a similar substance) used in such a way as to be a medium of communication; "the words were scribbled in pencil"; "this artist's favorite medium is pencil"