spheroid

adj. spheroidal, having a shape that is almost spherical

n. geometrical figure having a shape that is almost spherical

A spheroid is a quadric surface in three dimensions obtained by rotating an ellipse about one of its principal axes. Three particular cases of a spheroid are:If the ellipse is rotated about its major axis, the surface is a prolate spheroid (similar to the shape of a rugby ball). If the ellipse is rotated about its minor axis, the surface is an oblate spheroid (similar to the shape of the planet Earth). If the generating ellipse is a circle, the surface is a sphere (completely symmetric).
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Noun
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"
(synonym) ellipsoid of revolution
(hypernym) round shape

(n.)
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.
  

Mathematical figure closely approaching the geoid in form and size and used as a surface of reference for geodetic surveys. A reference spheroid or ellipsoid is a spheroid determined by revolving an ellipse about its shorter (polar) axis and used as a base for geodetic surveys of a large section of the Earth (such as the Clarke spheroid of 1866 which is used for geodetic surveys in the United States).