GYROIDAL

Gy‐roid″al (jī̍‐roid″al), a. [[Gr. γυ̑ροσ circle + -oid + -al.]] 1. 1. Spiral in arrangement or action.
2. 2. (Crystallog.) Having the planes arranged spirally, so that they incline all to the right (or left) of a vertical line; — said of certain hemihedral forms.
3. 3. (Opt.) Turning the plane of polarization circularly or spirally to the right or left.