Reciprocate

To exchange two things, with both parties giving one thing and taking another thing.

To give something else in response (where the "thing" may also be abstract, a feeling or action) To make a reciprocal gift.

"I gave them apples from my tree; they reciprocated with a pie and some apple jelly."

To move backwards and forwards, like a piston.

"A reciprocating engine."

To counter, retort or retaliate.