rain check vs supplication

rain check

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

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

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

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

supplication

noun
  • An act of supplicating; a humble request. 

  • The process by which a doctorate at Oxford university is officially requested after a thesis has been approved. 

  • In Ancient Rome, a solemn service or day decreed for giving formal thanks to the gods for victory, etc. 

  • A prayer or entreaty to a god. 

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