prop vs vary

prop

verb
  • To support or shore up something. 

  • To play rugby in the prop position. 

  • To manually start the engine of a propeller-driven aircraft with no electric starter by pulling vigorously on one of the propeller blades using the hands, so that the propeller can catch ignition. 

  • To position the feet of (a person) while sitting, lying down, or reclining so that the knees are elevated at a higher level. 

noun
  • The propeller of an aircraft. 

  • An item placed within an advertisement in order to suggest a style of living etc. 

  • An item placed on a stage or set to create a scene or scenario in which actors perform. 

  • An object placed against or under another, to support it; anything that supports. 

  • Any of the seashells in the game of props. 

  • A proposition, especially on an election-day ballot. 

  • The player on either side of the hooker in a scrum. 

  • propellant (“rocket fuel”) 

vary

verb
  • To be or act different from the usual. 

  • To make of different kinds; to make different from one another; to diversity; to variegate. 

  • To embellish; to change fancifully; to present under new aspects, as of form, key, measure, etc. See variation. 

  • Not to remain constant: to change with time or a similar parameter. 

  • To institute a change in, from a current state; to modify. 

  • To change with time or a similar parameter. 

  • To display differences. 

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