D defs.my
Entry 2 senses Webster, 1913

Gyration

/(jī̇*rā"shŭn)/ · Gy·ra·tion · IPA /ˌd͡ʒaɪˈɹeɪʃ(ə)n/
01 n. The act of turning or whirling, as around a fixed center; a circular or spiral motion; motion about an axis; rotation; revolution.
  1. 1.
    The act of turning or whirling, as around a fixed center; a circular or spiral motion; motion about an axis; rotation; revolution.
    “The gyrations of an ascending balloon.” De Quincey.
    “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.
  2. 2.
    One of the whorls of a spiral univalve shell.(Zool.)
Phrases & compounds
Center of gyration — See under Center.
Radius of gyration — the distance between the axis of a rotating body and its center of gyration.