rain check vs rover

rain check

noun
  • A reissue, at no extra charge, of a ticket for a baseball game or other outdoor event postponed or interrupted because of rain. 

  • to make good on any experience that the customer deems unsatisfactory. 

  • In social interactions, a deferred invitation, or deferred acceptance of an invitation. 

  • to provide a sold-out item or temporarily unavailable service at a later date for the running (usually special) price. 

rover

noun
  • The tenth defensive player in slow-pitch softball. 

  • A position that is one of three of a team's followers, who follow the ball around the ground. Formerly a position for short players, rovers in professional leagues are frequently over 183 cm (6'). 

  • A pirate. 

  • A randomly selected target. 

  • A vagabond, a tramp, an unsteady, restless person, one who by habit doesn't settle down or marry. 

  • A remotely-operated vehicle; ROV 

  • A defensive back position whose coverage responsibilities are a hybrid of those of a cornerback, safety and linebacker. 

  • One who roves, a wanderer, a nomad. 

  • A ball which has passed through all the hoops and would go out if it hit the stake but is continued in play; also, the player of such a ball. 

  • A pirate ship. 

  • A vehicle for exploring extraterrestrial bodies. 

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