D defs.my
Entry 3 senses Webster, 1913

Gyroidal

/(jī̇*roid"al)/ · Gy·roid·al · IPA
01 a. Spiral in arrangement or action.
  1. 1.
    Spiral in arrangement or action.
  2. 2.
    Having the planes arranged spirally, so that they incline all to the right (or left) of a vertical line; -- said of certain hemihedral forms.(Crystallog.)
  3. 3.
    Turning the plane of polarization circularly or spirally to the right or left.(Opt.)