nun vs priestress

nun

noun
  • A kind of pigeon with the feathers on its head like the hood of a nun. 

  • A member of a similar female community in other confessions. 

  • A member of a Christian religious community of women who live by certain vows and usually wear a habit, (Roman Catholicism, specifically) those living together in a cloister. 

  • The fourteenth letter of many Semitic alphabets/abjads (Phoenician, Aramaic, Hebrew, Syriac, Arabic and others). 

priestress

noun
  • A priestess. 

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