Cylindroid

Cyl"in*droid (s?l"?n-droid), n. [Gr. ky`lindros cylinder + -oid: cf. F. cylindroïde.] 1. A solid body resembling a right cylinder, but having the bases or ends elliptical.

2. (Geom.) A certain surface of the third degree, described by a moving straight line; -- used to illustrate the motions of a rigid body and also the forces acting on the body.