esquire vs sir

esquire

noun
  • A male member of the gentry ranking below a knight. 

  • A gentleman who attends or escorts a lady in public. 

  • A lawyer. 

  • A bearing somewhat resembling a gyron, but extending across the field so that the point touches the opposite edge of the escutcheon. 

  • An honorific sometimes placed after a man's name. 

sir

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

  • A man of a higher rank or position. 

  • to a teacher. 

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