folk vs heavy metal

folk

noun
  • People in general. 

  • The inhabitants of a region, especially the native inhabitants. 

  • One’s relatives, especially one’s parents. 

  • A particular group of people. 

adj
  • Of or pertaining to common people as opposed to ruling classes or elites. 

  • Of or pertaining to the inhabitants of a land, their culture, tradition, or history. 

  • Of or related to local building materials and styles. 

  • Believed or transmitted by the common people; not academically correct or rigorous. 

heavy metal

noun
  • Great influence or power. 

  • 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.) 

  • guns or shot of large size. 

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