from
The Collaborative International Dictionary of English v.0.48
Rotary \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.
[1913 Webster]
{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.
[1913 Webster]