landfill vs lava

landfill

noun
  • A site at which refuse is buried under layers of earth. 

  • The material so disposed of. 

verb
  • To dispose of (garbage) by burying it at a landfill site. 

lava

noun
  • The molten rock ejected by a volcano from its crater or fissured sides. 

  • Magma. 

  • A shade of red, named after the volcanic lava. 

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