The Collaborative International Dictionary of English v.0.48:

Gyration \Gy*ra"tion\ (j[-i]*r[=a]"sh[u^]n), n.
   1. The act of turning or whirling, as around a fixed center;
      a circular or spiral motion; motion about an axis;
      rotation; revolution.
      [1913 Webster]

            The gyrations of an ascending balloon. --De Quincey.
      [1913 Webster]

            If a burning coal be nimbly moved round in a circle,
            with gyrations continually repeated, the whole
            circle will appear like fire.         --Sir I.
                                                  Newton.
      [1913 Webster]

   2. (Zool.) One of the whorls of a spiral univalve shell.
      [1913 Webster]

   Center of gyration. (Mech.) See under Center.

   Radius of gyration, the distance between the axis of a
      rotating body and its center of gyration. --Rankine.
      [1913 Webster]

WordNet (r) 3.0 (2006):

gyration
    n 1: a single complete turn (axial or orbital); "the plane made
         three rotations before it crashed"; "the revolution of the
         earth about the sun takes one year" [syn: rotation,
         revolution, gyration]
    2: the act of rotating in a circle or spiral [syn: gyration,
       whirling]

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "gyration":
   angular momentum, angular motion, angular velocity, axial motion,
   bowling, centrifugation, circuit, circulation, circumgyration,
   circumrotation, circumvolution, full circle, gyre, pivoting,
   reeling, revolution, roll, rolling, rotation, rotational motion,
   round, spin, spinning, swinging, swirling, swiveling, trolling,
   trundling, turbination, turn, turning, volutation, volution, wheel,
   wheeling, whir, whirl, whirling