heavy metal vs rock and roll

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. 

rock and roll

noun
  • A genre of popular music that evolved in the 1950s from a combination of rhythm and blues and country music, characterized by electric guitars, strong rhythms, and youth-oriented lyrics. 

  • An intangible feeling, philosophy, belief or allegiance relating to rock music, characterized by unbridled enthusiasm, hedonism, and cynical regard for authoritarian bodies. 

  • Dole, payment by the state to the unemployed. 

  • The full automatic fire capability selection on a selective fire weapon. 

  • The ability to run the picture and audio back and forth in synchronization, allowing the correction of mistakes during dubbing. 

  • A style of vigorous dancing associated with this genre of music. 

verb
  • To play rock and roll music. 

  • To start, commence, begin, get moving. 

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