air vs heavy metal

air

noun
  • Pretension; snobbishness; pretence that one is better than others. 

  • understood as a gaseous mixture of nitrogen, oxygen, and various trace gases. 

  • The apparently open space above the ground which this substance fills, (historical) formerly thought to be limited by the firmament but (meteorology) now considered to be surrounded by the near vacuum of outer space. 

  • understood as a particular local substance with supposed effects on human health. 

  • A song, especially a solo; an aria. 

  • A jump in which one becomes airborne. 

  • A feeling or sense. 

  • The substance constituting Earth's atmosphere 

  • A sense of poise, graciousness, or quality. 

  • Nothing; absence of anything. 

  • Publicity. 

  • A breeze; a gentle wind. 

  • A television or radio signal; (by extension) media broadcasts in general. 

  • An air conditioner or the processed air it produces. 

  • understood as one of the four elements of the ancient Greeks and Romans. 

verb
  • To be broadcast. 

  • To broadcast (a television show etc.). 

  • To discuss varying viewpoints on a given topic. 

  • To bring (something) into contact with the air, so as to freshen or dry it. 

  • To ignore (a person). 

  • To let fresh air into a room or a building, to ventilate. 

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 air and heavy metal occurred in a corpus of books? (source: Google Ngram Viewer )