trochoid

== English == === Etymology === From Ancient Greek τροχοειδής (trokhoeidḗs), from τροχός (trokhós, “wheel”) + εἶδος (eîdos, “form, image”). === Pronunciation === === Noun === trochoid (plural trochoids) (geometry) The curve traced by a point on a circle as it rolls along a straight line (malacology) An organism or fossil with a trochoid shell (especially one in the gastropod family Trochidae), or the shell itself. === Adjective === trochoid (comparative more trochoid, superlative most trochoid) Capable of rolling. Allowing rotation. (malacology, of a shell or fossil) High-spired; conical.