combine vs cooperate

combine

verb
  • To bring (two or more things or activities) together; to unite. 

  • To have two or more things or properties that function together. 

  • In the game of casino, to play a card which will take two or more cards whose aggregate number of pips equals those of the card played. 

  • To come together; to unite. 

noun
  • Especially, a joint enterprise of whatever legal form for a purpose of business or in any way promoting the interests of the participants, sometimes with monopolistic or fraudulent intentions. 

  • An artwork falling between painting and sculpture, having objects embedded into a painted surface. 

  • An industrial conglomeration in a socialist country, particularly in the former Soviet bloc. 

  • A Test match in which applicants play in the hope of earning a position on a professional football team. 

  • A combine harvester 

cooperate

verb
  • To work or act together, especially for a common purpose or benefit. 

  • To function in harmony, side by side 

  • To allow for mutual unobstructed action 

  • To engage in economic cooperation. 

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