Tro"choid (?), n. [Gr. a wheel + -oid; cf. F. trochoide. See Troche.] Geom.

The curve described by any point in a wheel rolling on a line; a cycloid; a roulette; in general, the curve described by any point fixedly connected with a moving curve while the moving curve rolls without slipping on a second fixed curve, the curves all being in one plane. Cycloids, epicycloids, hypocycloids, cardioids, etc., are all trochoids.


© Webster 1913.

Tro"choid, a.

1. Anat.

Admitting of rotation on an axis; -- sometimes applied to a pivot joint like that between the atlas and axis in the vertebral column.

2. Zool.

Top-shaped; having a flat base and conical spire; -- said of certain shells.

3. Zool.

Of or pertaining to the genus Trochus or family Trochidae.


© Webster 1913.