endgame vs runoff

endgame

noun
  • The final stage of any game. 

  • The final stage of a game of chess, when there are few pieces left. 

  • The final stage of an extended process or course of events, especially with the implication of the imminent realization of a masterful strategy or plan. 

  • The gameplay available in a massively multiplayer online role-playing game for players who have completed all of the preset challenges. 

  • The final stage of a game of bridge, when there are few cards left. 

adj
  • Having become canon by the end of the plot of a work of fiction or speculated to be intended to become such. 

runoff

noun
  • A second or further round of a competition, after other competitors (often all but the last two) have been eliminated. 

  • That portion of precipitation or irrigation on an area which does not infiltrate or evaporate, but instead is discharged from the area. 

  • A second or further round of an indecisive election, after other candidates (often all but the last two) have been eliminated. 

  • Dissolved chemicals, etc, included in such water. 

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