Webster's Revised Unabridged Dictionary · 1913

Reciprocate

Reciprocate (re*sip"ro*kāt) , intransitive verb

[Latin reciprocatus, past participle of reciprocare. See Reciprocal.]

To move forward and backward alternately; to recur in vicissitude; to act interchangeably; to alternate.
One brawny smith the puffing bellows plies, And draws and blows reciprocating air. — Dryden
Collocations (2)
Reciprocating engine , a steam, air, or gas engine, etc., in which the piston moves back and forth; -- in distinction from a rotary engine, in which the piston travels continuously in one direction in a circular path.
Reciprocating motion (Mechanics) , motion alternately backward and forward, or up and down, as of a piston rod.

Reciprocate , transitive verb

To give and return mutually; to make return for; to give in return; to interchange; to alternate; as, to reciprocate favors. — Cowper