grandfather vs sir

grandfather

noun
  • A male forefather. 

  • A father of someone's parent. 

  • The archived older version of a file that immediately preceded the father file. 

verb
  • To retain discontinued laws or rules for (a thing, person or organization previously affected by them). 

  • To be, or act as, a grandfather to. 

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 grandfather and sir occurred in a corpus of books? (source: Google Ngram Viewer )