ellipsoid

[ih-lip-soid]

noun

Geometry. a solid figure all plane sections of which are ellipses or circles. Typical equation: (x2/a2) + (y2/b2) + (z2/c2) = 1.

adjective

ellipsoidal.

Origin of ellipsoid

From the French word ellipsoïde, dating back to 1715–25. See ellipse, -oid

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for ellipsoid

Historical Examples of ellipsoid

The fruit is a small, ellipsoid drupe, which is bluish-black when ripe.
Fruits of the Hawaiian Islands
Gerrit Parmile Wilder
Of the two eggs, one is of an ovoid form, having much the shape of a hen's egg; and the other is an ellipsoid.
Remarks on some fossil impressions in the sandstone rocks of Connecticut River
John Collins Warren
Its form is that of an ellipsoid, with a major axis 26 millimetres in length, while the minor axis measures 11 millimetres.
More Hunting Wasps
J. Henri Fabre
The form of the latter is at first globular, then ellipsoid, and more or less curved.
Fungi: Their Nature and Uses
Mordecai Cubitt Cooke
Sporangia globose or ovoid to ellipsoid or oblong, erect or sometimes inclined or even nodding.
The Myxomycetes of the Miami Valley, Ohio
A. P. Morgan

British Dictionary definitions for ellipsoid

ellipsoid

noun

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- axes
a solid having this shapethe earth is an ellipsoid

Derived Formsellipsoidal (ɪlɪpˈsɔɪdəl, ˌɛl-), adjective

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for ellipsoid

1721; see ellipse + -oid. From 1861 as an adjective (earlier adjective was ellipsoidal).

ellipsoid in Science

ellipsoid

[ĭ-lĭp′soid′]

A three-dimensional geometric figure resembling a flattened sphere. Any cross section of an ellipsoid is an ellipse or circle. An ellipsoid is generated by rotating an ellipse around one of its axes.