heavy metal

noun

1. any metal with a specific gravity of 5.0 or greater, especially one that is toxic to organisms, as lead, mercury, copper, and cadmium.
2. aggressive and heavily amplified rock music, commonly performed by groups that wear spectacular or bizarre costumes.

noun

1. 1. a type of rock music characterized by a strong beat and amplified instrumental effects, sometimes with violent, or nihilistic lyrics
   2. (as modifier)a heavy-metal band
2. a metal with a high specific gravity
3. military large guns or shot