\Ro"ta*ry\, a. [L. rota a wheel. See {Roll}, v., and cf.
{barouche}, {Rodomontade}, {Rou['e]}, {Round}, a., {Rowel}.]
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}, steam engine in which the continuous
   rotation of the shaft is produced by the direct action of
   the steam upon rotating devices which serve as pistons,
   instead of being derived from a reciprocating motion, as
   in the ordinary engine; a steam turbine; -- called also
   {rotatory engine}.

{Rotary pump}, a pump in which the fluid is impelled by
   rotating devices which take the place of reciprocating
   buckets or pistons.

{Rotary shears}, shears, as for cloth, metal, etc., in which
   revolving sharp-edged or sharp-cornered wheels do the
   cutting.

{Rotary valve}, a valve acting by continuous or partial
   rotation, as in the four-way cock.