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]

WordNet (r) 3.0 (2006):

rotary
    adj 1: relating to or characterized by rotation; "rotary dial"
    2: describing a circle; moving in a circle; "the circular motion
       of the wheel" [syn: circular, rotary, orbitual]
    n 1: a road junction at which traffic streams circularly around
         a central island; "the accident blocked all traffic at the
         rotary" [syn: traffic circle, circle, rotary,
         roundabout]
    2: electrical converter consisting of a synchronous machine that
       converts alternating to direct current or vice versa [syn:
       synchronous converter, rotary, rotary converter]

Moby Thesaurus II by Grady Ward, 1.0:

112 Moby Thesaurus words for "rotary":
   O-shaped, alternate, ambagious, ascending, axial, back,
   back-flowing, backhanded, backward, beating, carrefour, circling,
   circuitous, circular, circumgyratory, circumvolutory, cloverleaf,
   crossing, crosspoint, crossroad, crosswalk, crossway, cyclic,
   cyclonic, descending, deviating, deviative, devious, digressive,
   discursive, down-trending, downward, drifting, epochal, even,
   every other, excursive, flowing, fluent, flying, flyover, going,
   grade crossing, gulfy, gyral, gyrational, gyratory, gyrostatic,
   helical, indirect, intercrossing, intermittent, intersection,
   isochronal, level crossing, meandering, measured, metronomic,
   mounting, oblique, orbital, oscillatory, out-of-the-way,
   overcrossing, overpass, passing, periodical, plunging, progressive,
   pulsing, reciprocal, recurrent, recurring, reflowing, refluent,
   regressive, retrogressive, rhythmic, rising, rotational, rotatory,
   round, roundabout, running, rushing, seasonal, serial, sideward,
   sinking, soaring, spiral, steady, streaming, swirly, tornadic,
   traffic circle, trochilic, undercrossing, undulant, undulatory,
   up-trending, upward, vertiginous, viaduct, vortical, wavelike,
   wheeling, whirlabout, whirligig, whirlwindish, whirlwindy,
   whirly