fantasia vs mirage

fantasia

noun
  • A form of instrumental composition with a free structure and improvisational characteristics; specifically, one combining a number of well-known musical pieces. 

  • A traditional festival of the inhabitants of the Maghreb (in northwest Africa) featuring exhibitions of horsemanship. 

  • Any work which is unstructured or comprises other works of different genres or styles. 

mirage

verb
  • To cause to appear as or like a mirage. 

noun
  • An optical phenomenon in which light is refracted through a layer of hot air close to the ground, often giving the illusion of a body of water. 

  • An illusion. 

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