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# ellipsoid

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

## Origin of .css-1fxfie5{font-size:22px;}@media (max-width:768px){.css-1fxfie5{font-size:18px;margin:0 10px 10px 0;word-break:break-all;word-wrap:break-word;-webkit-hyphens:auto;-moz-hyphens:auto;-ms-hyphens:auto;hyphens:auto;line-height:22px;}}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. 2018

## Examples from the Web for ellipsoid

### Historical Examples

• #### The fruit is a small, ellipsoid drupe, which is bluish-black when ripe.

Fruits of the Hawaiian Islands

Gerrit Parmile Wilder

• #### 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.

British Dictionary definitions for ellipsoid

# ellipsoid

noun
1. 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
2. a solid having this shapethe earth is an ellipsoid
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 forellipsoid

### n.

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