To combine in action; to co-operate. Obsolete.

intransitive. To combine in action or aim; to act in purposive combination, union, or harmony.

To combine in action, to co-operate. of persons, etc.

intransitive. To work together, act in conjunction (with another person or thing, to an end or… Of things: To concur in producing an effect.

To help in concert, co-operate helpfully. transitive and intransitive.

intransitive. To act together. rare.

in the (or a) quill: in a body; in concert; together. to jump in quill: to act simultaneously or in harmony.

intransitive. To work together, act in conjunction (with another person or thing, to an end or purpose, or in a work). of persons.

intransitive. To co-operate.

intransitive. To act in unison; to work in harmony; to cooperate. Also: to agree, get on well together.

intransitive. Of people: to come together in a body, esp. to offer aid or support to a person, cause, etc.; to unite for a common purpose. Frequently…

slang (chiefly British and Irish English). to row in: to join in (or, occasionally, thrust oneself into) some scheme, conspiracy, or project; to…

intransitive. To work in conjunction with another or others, to co-operate; esp. in a literary or artistic production, or the like.

to play ball (with): to act fairly (with), to cooperate (with).

intransitive. colloquial (originally U.S.). To cooperate, comply, agree; = sense 14f. Also: to pretend to agree or cooperate. Frequently with with.

intransitive. colloquial. To cooperate, comply, agree; to do what is required of one. Frequently in negative contexts. Cf. ball, n.1 phrases 1i.