combination vs simultaneity

combination

noun
  • The act of combining, the state of being combined or the result of combining. 

  • One or more elements selected from a set without regard to the order of selection. 

  • An association or alliance of people for some common purpose. 

  • A combination shot; a billiard; a shot where the cue ball hits a ball that strikes another ball on the table. 

  • A sequence of numbers or letters used to open a combination lock. 

  • A rapid sequence of punches or strikes in boxing or other combat sports. 

  • A motorcycle and sidecar. 

  • An object formed by combining. 

simultaneity

noun
  • The quality or state of being simultaneous; simultaneousness. 

  • More than one complete musical texture occurring at the same time. This first appeared in the music of Charles Ives, and is common in the music of Conlon Nancarrow, and others. 

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