ellipsoid

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A geometric surface, all of whose plane sections are either ellipses or circles.

from The Century Dictionary.

• noun In anthropology, a cranium the norma verticalis of which has an ellipsoidal form.
• noun In geometry, a solid figure all plane sections of which are ellipses or circles.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Pertaining to, or shaped like, an ellipsoid.
• noun (Geom.) A solid, all plane sections of which are ellipses or circles. See conoid, n., 2 (a).
• noun 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun mathematics a surface, all of whose cross sections are elliptic or circular (includes the sphere)
• noun geography Such a surface used as a model of the shape of the earth.
• adjective Shaped like an ellipse; elliptical.
• adjective mathematics Of or pertaining to an ellipse.
• adjective botany Having the tridimensional shape of an ellipse rotated on its long axis.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a surface whose plane sections are all ellipses or circles
• adjective having the nature or shape of an ellipsoid