bonus vs pourboire

bonus

noun
  • An extra sum given as a premium, e.g. to an employee or to a shareholder. 

  • Something extra that is good; an added benefit. 

  • An addition to the player's score based on performance, e.g. for time remaining. 

  • One or more free throws awarded to a team when the opposing team has accumulated enough fouls. 

verb
  • To pay a bonus, premium 

pourboire

noun
  • A tip (extra money given to e.g. a waiter in appreciation of service), especially in French contexts. 

  • A bribe. 

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