Heavy metals Meaning, Definition & Usage

  1. noun 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)
    heavy metal.
  2. noun loud and harsh sounding rock music with a strong beat; lyrics usually involve violent or fantastic imagery
    heavy metal; heavy metal music.

WordNet

Definitions
  1. . (Chem.) See under Metal.
Definitions
  1. (Chem.), the metallic elements not included in the groups of the alkalies, alkaline earths, or the earths; specifically, the heavy metals, as gold, mercury, platinum, lead, silver, etc.

Webster 1913