parasol vs rooftop

parasol

noun
  • A roof or covering of a structure designed to provide cover from wind, rain, or sun. 

  • A miniature paper umbrella used as a decoration in tropical-themed cocktails. 

  • The parasol mushroom, Macrolepiota procera 

  • A small light umbrella used as protection from the sun. 

  • Any of various Asian species of libellulid dragonfly of the genus Neurothemis. 

verb
  • To protect with, or as if with, a parasol; to shade. 

rooftop

noun
  • The area atop a roof. 

  • The top layer of a roof; the material covering or composing a roof. 

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