to give and take (something) mutually
The two countries reciprocated pledges of friendship
to return (something) in kind or degree
You should reciprocate a compliment gracefully
to make a return for something
He stroked the cat and it reciprocated by purring
to move forwards and backwards alternately
a reciprocating valve
reciprocation /-ʹkaysh(ə)n/ noun
reciprocative /-kətiv/ adj
reciprocator noun