The Collaborative International Dictionary of English v.0.48:

Rotatory \Ro"ta*to*ry\, a. [Cf. F. rotatoire. See Rotate,
   Rotary.]
   1. Turning as on an axis; rotary.
      [1913 Webster]

   2. Going in a circle; following in rotation or succession;
      as, rotatory assembles. --Burke.
      [1913 Webster]

   3. (Opt.) Producing rotation of the plane of polarization;
      as, the rotatory power of bodies on light. See the Note
      under polarization. --Nichol.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Rotatory \Ro"ta*to*ry\, n. (Zool.)
   A rotifer. [R.] --Kirby.
   [1913 Webster]

WordNet (r) 3.0 (2006):

rotatory
    adj 1: of or relating to or characteristic or causing an axial
           or orbital turn [syn: rotatory, revolutionary]