# ellipsoid

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## ellipsoid

a geometric surface, symmetrical about the three coordinate axes, whose plane sections are ellipses or circles. Standard equation:

*x*^{2}/*a*^{2}+*y*^{2}/*b*^{2}+*z*^{2}/*c*^{2}= 1, where ?*a*, ?*b*, ?*c*are the intercepts on the*x-, y-,*and*z-*axesCollins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

## ellipsoid

(i-**lip**-soid) A surface or solid whose plane sections are circles or ellipses. An ellipse rotated about its major or minor axis is a particular type of ellipsoid, called a

*prolate spheroid*(major axis) or an

*oblate spheroid*(minor axis).

Collins Dictionary of Astronomy © Market House Books Ltd, 2006

The following article is from

*The Great Soviet Encyclopedia*(1979). It might be outdated or ideologically biased.## Ellipsoid

a closed central quadric surface. An ellipsoid has a center of symmetry *O* (see Figure 1) and three axes of symmetry, which are called the axes of the ellipsoid. The plane sections of

ellipsoids are ellipses; in particular, one can always find a plane section that is a circle. In a suitable coordinate system the equation of an ellipsoid has the form

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

## ellipsoid

[ə′lip‚sȯid] (mathematics)

A surface whose intersection with every plane is an ellipse (or circle).

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.