intr.v. co·op·er·at·ed, co·op·er·at·ing, co·op·er·ates
1. To work or act together toward a common end or purpose.
2. To acquiesce willingly; be compliant: asked the child to cooperate and go to bed.
3. To form an association for common, usually economic, benefit: When buyers cooperate, they can make large wholesale purchases at a discount.
[Late Latin cooperārī, cooperāt- : Latin co-, co- + operārī, to work (from opus, oper-, work; see op- in the Appendix of Indo-European roots).]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.