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Alternative forms[edit]


Originated 1595–1605 from Late Latin cooperatus ‎(work with). See co- + operate.


  • IPA(key): /koʊˈɒpəɹeɪt/, /kuˈɒpəɹeɪt/
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cooperate ‎(third-person singular simple present cooperates, present participle cooperating, simple past and past participle cooperated)

  1. (intransitive) To work or act together, especially for a common purpose or benefit.
    • 2012 November 7, Matt Bai, “Winning a Second Term, Obama Will Confront Familiar Headwinds”[1], New York Times:
      In polling by the Pew Research Center in November 2008, fully half the respondents thought the two parties would cooperate more in the coming year, versus only 36 percent who thought the climate would grow more adversarial.
  2. (intransitive) To allow for mutual unobstructed action
  3. (intransitive) To function in harmony, side by side
  4. (intransitive) To engage in economic cooperation.

Usage notes[edit]

The usual pronunciation of 'oo' is /uː/ or /ʊ/. The dieresis in the spelling coöperate emphasizes that the second o begins a separate syllable. However, the dieresis is becoming increasingly rare in US English typography, so the spelling cooperate predominates. See also Appendix:Dieresis.


Related terms[edit]



  • cooperate” in The American Heritage Dictionary of the English Language, Fourth Edition, Houghton Mifflin Company, 2000.
  • cooperate” in Unabridged, v1.0.1, Lexico Publishing Group, 2006.
  • "cooperate" in WordNet 2.0, Princeton University, 2003.




  1. second-person plural present indicative of cooperare
  2. second-person plural imperative of cooperare
  3. feminine plural of cooperato