( BrE also co-operate ) / kəʊˈɒpəreɪt; NAmE koʊˈɑːp-/ verb [ v ] cooperate (with sb) (in / on sth)
1.
to work together with sb else in order to achieve sth :
The two groups agreed to cooperate with each other.
They had cooperated closely in the planning of the project.
2.
to be helpful by doing what sb asks you to do :
Their captors told them they would be killed unless they cooperated.
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WORD ORIGIN
late 16th cent.: from ecclesiastical Latin cooperat- worked together, from the verb cooperari , from co- together + operari to work.