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Definition of "co-" [co-]

  • Together; joint; jointly; mutually: coeducation. (prefix)
  • Partner or associate in an activity: coauthor; cofounder. (prefix)
  • Subordinate or assistant: copilot. (prefix)
  • To the same extent or degree: coextensive. (prefix)
  • Complement of an angle: cotangent. (prefix)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Use "co-" in a sentence
  • "Though he retired from Bain in February 1999, Romney, 64, continues to benefit from the firm's profitable private equity funds and to invest alongside them in so-called "co- investment" vehicles, both of which generate income taxed at the 15 percent rate."
  • "A Dangerous Method is a Canadian/German co- production."
  • "Next among the six comes Dustin Moskovitz, a co- founder."