The Collaborative International Dictionary of English v.0.48:

Conoid \Co"noid\ (k[=o]"noid), n. [Gr. kwnoeidh`s conical;
   kw^nos cone + e'i^dos form: cf. F. cono["i]de.]
   1. Anything that has a form resembling that of a cone.
      [1913 Webster]

   2. (Geom.)
      (a) A solid formed by the revolution of a conic section
          about its axis; as, a parabolic conoid, elliptic
          conoid, etc.; -- more commonly called paraboloid,
          ellipsoid, etc.
      (b) A surface which may be generated by a straight line
          moving in such a manner as always to meet a given
          straight line and a given curve, and continue parallel
          to a given plane. --Math. Dict.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ellipsoid \El*lip"soid\, n. [Ellipse + -oid: cf. F. ellipsoide.]
   (Geom.)
   A solid, all plane sections of which are ellipses or circles.
   See Conoid, n., 2
   (a) .
       [1913 Webster]

   Note: The ellipsoid has three principal plane sections, a, b,
         and c, each at right angles to the other two, and each
         dividing the solid into two equal and symmetrical
         parts. The lines of meeting of these principal sections
         are the axes, or principal diameters of the ellipsoid.
         The point where the three planes meet is the center.
         [1913 Webster]

   Ellipsoid of revolution, a spheroid; a solid figure
      generated by the revolution of an ellipse about one of its
      axes. It is called a prolate spheroid, or prolatum, when
      the ellipse is revolved about the major axis, and an
      oblate spheroid, or oblatum, when it is revolved about the
      minor axis. Ellipsoid

The Collaborative International Dictionary of English v.0.48:

Ellipsoid \El*lip"soid\, Ellipsoidal \El`lip*soi"dal\, a.
   Pertaining to, or shaped like, an ellipsoid; as, ellipsoid or
   ellipsoidal form. Elliptic

WordNet (r) 3.0 (2006):

ellipsoid
    adj 1: having the nature or shape of an ellipsoid [syn:
           ellipsoid, ellipsoidal, spheroidal]
    n 1: a surface whose plane sections are all ellipses or circles;
         "the Earth is an ellipsoid"

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "ellipsoid":
   ball, balloon, bladder, blob, boll, bolus, bubble, bulb, bulbil,
   bulblet, geoid, globe, globelet, globoid, globule, glomerulus, gob,
   gobbet, knob, knot, oblate spheroid, orb, orbit, orblet, pellet,
   prolate spheroid, rondure, sphere, spheroid, spherule