khan vs monarch

khan

noun
  • A ruler over various Turkish, Tatar and Mongol peoples in the Middle Ages. 

  • A noble or man of rank in various Muslim countries of Central Asia, including Afghanistan. 

  • A caravanserai; a resting-place for a travelling caravan. 

  • An Ottoman sultan. 

monarch

noun
  • The ruler of an absolute monarchy or the head of state of a constitutional monarchy. 

  • The monarch butterfly, Danaus plexippus, and others of genus Danaus, found primarily in North America, so called because of the designs on its wings. 

  • A stag which has sixteen or more points or tines on its antlers. 

  • The chief or best thing of its kind. 

  • A police officer. 

  • Any bird of the family Monarchidae. 

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