1. a metal of relatively high density (specific gravity greater than about 5) or of high relative atomic weight (especially one that is poisonous like mercury or lead) • Hypernyms: metallic element, metal, alloy 2. loud and harsh sounding rock music with a strong beat; lyrics usually involve violent or fantastic imagery • Syn: heavy metal music • Hypernyms: rock 'n' roll, rock'n'roll, rock-and-roll, rock and roll, rock, rock music