v. 1 tr. return or requite (affection etc.). 2 intr. (foll. by with) offer or give something in return (reciprocated with an invitation to lunch). 3 tr. give and receive mutually; interchange. 4 a intr. (of a part of a machine) move backwards and forwards. b tr. cause to do this. reciprocating engine an engine using a piston or pistons moving up and down in cylinders. reciprocation n. reciprocator n.
[ L reciprocare reciprocat- (as RECIPROCAL) ]