heavy metal vs soul

heavy metal

noun
  • A genre descended from rock music, characterized by massive sound, highly amplified distortion, and overall loudness, often with extended guitar solos, and lyrics that involve aggressive or fantastic imagery. 

  • Any metal that has a specific gravity greater than about 5, especially one, such as lead, that is poisonous and may be a hazard in the environment. (There are many different definitions of what counts as a heavy metal; see Heavy metals for a discussion.) 

  • Great influence or power. 

  • guns or shot of large size. 

soul

noun
  • Soul music. 

  • The spirit or essence of anything. 

  • The spirit or essence of a person usually thought to consist of one's thoughts and personality, often believed to live on after the person's death. 

  • A kind of submanifold involved in the soul theorem of Riemannian geometry. 

  • A person, especially as one among many. 

  • An individual life. 

  • Life, energy, vigor. 

verb
  • To beg on All Soul's Day. 

How often have the words heavy metal and soul occurred in a corpus of books? (source: Google Ngram Viewer )