ellipsoid

[ ih-lip-soid ]

noun

1. Geometry. a solid figure all plane sections of which are ellipses or circles. Typical equation: ( x 2 / a 2 ) + ( y 2 / b 2 ) + ( z 2 / c 2 ) = 1.

adjective

1. ellipsoidal.

ellipsoid

/ ɪˈlɪpsɔɪd; ɪlɪpˈsɔɪdəl; ˌɛl- /

noun

1. 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 shape

      the earth is an ellipsoid

ellipsoid

/ ĭ-lĭp′soid′ /

1. 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.

Derived Forms

• ellipsoidal, adjective

Word History and Origins

Origin of ellipsoid¹

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

Example Sentences

At the start of the experiment, the team molded the clay into a "half ellipsoid" or half of an oval shape.

From Scientific American

This is because the Earth is not shaped like a perfect sphere but rather closer to an ellipsoid, with its thickness from the equator being roughly 70,000 feet wider than from the poles.

From Salon

Dissecting these death-exposed flies revealed activity in the ellipsoid body, which integrates sensory information in the brain.

From New York Times

The crucial dispute between Cartesians and Newtonians was over the shape of the Earth: Newton predicted an oblate ellipsoid, or flattened, Earth, while the Cartesians had predicted a prolate ellipsoid, or egg-shaped, Earth.

From Literature

Satellites, and therefore global positioning systems, measure height relative to a smoothed out mathematical approximation of the Earth’s shape called an ellipsoid.

From New York Times