greenhouse vs hill

greenhouse

verb
  • To place (plants) in a greenhouse. 

  • To nurture in order to promote growth. 

noun
  • A building used to grow plants, particularly one with large glass windows or plastic sheeting to trap heat from sunlight even in intemperate seasons or climates. 

  • A hot state in global climate. 

  • A structure that shields the operating table to protect against bacteria. 

hill

verb
  • To heap or draw earth around plants. 

  • To form into a heap or mound. 

noun
  • A single cluster or group of plants growing close together, and having the earth heaped up about them. 

  • An elevated landmass smaller than a mountain. 

  • A heap of earth surrounding a plant. 

  • A sloping road. 

  • The pitcher’s mound. 

  • The raised portion of the surface of a vinyl record. 

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