[mod. ad. Gr. κυλινδρο-ειδής cylinder-like: see -OID.]
1. A figure resembling a cylinder; spec. one on an elliptical base, an elliptic cylinder.
1663. Dary, in Rigaud, Corr. Sci. Men (1841), I. 99. I call them cylindroids (by which I mean) a solid contained under three surfaces.
1704. J. Harris, Lex. Techn., Cylindroid, is a Solid Figure with Elliptical Bases, parallel, and alike situated.
1879. Sir G. G. Scott, Lect. Archit., I. 239. That the vaulting surfaces should be portions of cylinders or regular cylindroids.
2. A conoidal cubic surface of fundamental importance in the theory of screws and complexes.
1871. Ball, Theory of Screws, in Trans. R. Irish Acad., 13 Nov.
