reciprocating (adj.)

"moving backwards and forwards," 1690s, present-participle adjective from reciprocate (v.). Specifically of machines, "having reciprocating parts," by 1822.

Reciprocating engine. A form of engine in which the piston and piston-rod move back and forth in a straight line, absolutely relative to the cylinder, as in oscillating-cylinder engines: in contradistinction to rotary engine. [Century Dictionary, 1895]

updated on May 19, 2021