Rō'ta-ry, a.

a. [From Lat. rota, wheel.] Turning, as a wheel on its axis; pertaining to, or resembling, the motion of a wheel on its axis; rotatory; as, rotary motion.

Rotary engine, a steam-engine in which a continuous motion round an axis is produced by the direct action of the steam, instead of being derived from a reciprocating motion, as in the ordinary engine;—called also rotatory engine.—Rotary pump, a machine consisting of one or more projections acting as plungers, fixed to an axle, and revolving in a cylindrical case, for lifting or forcing fluids.