institute vs roof

institute

noun
  • The building housing such an institution 

  • An organization founded to promote a cause 

  • The person to whom an estate is first given by destination or limitation. 

  • An institution of learning; a college, especially for technical subjects 

verb
  • To invest with the spiritual charge of a benefice, or the care of souls. 

  • To nominate; to appoint. 

  • To begin or initiate (something); to found. 

roof

noun
  • The top external level of a building. 

  • The external covering at the top of a building. 

  • The upper part of a cavity. 

  • An overhanging rock wall. 

  • The surface or bed of rock immediately overlying a bed of coal or a flat vein. 

verb
  • To cover or furnish with a roof. 

  • To traverse buildings by walking or climbing across their roofs. 

  • To put into prison, to bird. 

  • To shelter as if under a roof. 

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