Cylindroid /(s?l"?n-droid)/

Cyl·in·droid

Cylindroid

n.
  1. A solid body resembling a right cylinder, but having the bases or ends elliptical.
  2. 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. (Geom.)