Sir vs knight

Sir

noun
  • The titular prefix given to a knight or baronet. 

knight

noun
  • A person on whom a knighthood has been conferred by a monarch. 

  • A minor nobleman with an honourable military rank who had served as a page and squire. 

  • An armored and mounted warrior of the Middle Ages. 

  • A chess piece, often in the shape of a horse's head, that is moved two squares in one direction and one at right angles to that direction in a single move, leaping over any intervening pieces. 

  • A person obliged to provide knight service in exchange for maintenance of an estate held in knight's fee. 

  • A brave, chivalrous and honorable man devoted to a noble cause or love interest. 

  • Any of various nymphalid butterflies of the genus Ypthima. 

  • A young servant or follower; a trained military attendant in service of a lord. 

  • Any mushroom belonging to genus Tricholoma. 

verb
  • To confer knighthood upon. 

  • To promote (a pawn) to a knight. 

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