trochoid

Etymology
From, from +.

Noun

 * 1)  The curve traced by a point on a circle as it rolls along a straight line
 * 2)  An organism or fossil with a trochoid shell (especially one in the gastropod family ), or the shell itself.

Adjective

 * 1) Capable of rolling.
 * 2) Allowing rotation.
 * 3)  High-spired; conical. Bolma_bartschi_001.jpg