The Collaborative International Dictionary of English v.0.48:

Spheroid \Sphe"roid\, n. [L. spheroides ball-like, spherical,
   Gr. ???; ???? sphere + e'i^dos form: cf. F. sph['e]ro["i]de.]
   A body or figure approaching to a sphere, but not perfectly
   spherical; esp., a solid generated by the revolution of an
   ellipse about one of its axes.
   [1913 Webster]

   Oblate spheroid, Prolate spheroid. See Oblate,
      Prolate, and Ellipsoid.
      [1913 Webster]

WordNet (r) 3.0 (2006):

spheroid
    n 1: a shape that is generated by rotating an ellipse around one
         of its axes; "it looked like a sphere but on closer
         examination I saw it was really a spheroid" [syn:
         spheroid, ellipsoid of revolution]