grand vizier vs sir

grand vizier

noun
  • A figure of great authority and power. 

  • The greatest minister of a sultan, with absolute power of attorney and, in principle, dismissable only by the sultan himself. 

sir

noun
  • A man of a higher rank or position. 

  • to a teacher. 

  • to a knight or other low member of the peerage. 

  • to a superior military officer. 

  • A respectful term of address to a man of higher rank or position 

  • A respectful term of address to an adult male (often older), especially if his name or proper title is unknown. 

verb
  • To address (someone) using "sir". 

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