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) 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.

<mechanics> Reciprocating motion, motion alternately backward and forward, or up and down, as of a piston rod.

Origin: L. Reciprocatus, p. P. Of reciprocare. See Reciprocal.

(01 Mar 1998)