heavy metal vs modern

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. 

modern

noun
  • Someone who lives in modern times. 

adj
  • Pertaining to the modern period (c.1800 to contemporary times), particularly in academic historiography. 

  • Pertaining to a current or recent time and style; not ancient. 

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