ellipsoid

[ih-lip-soid]

noun

1. Geometry.,  a solid figure all plane sections of which are ellipses or circles. Typical equation: (x 2 / a2 ) + (y 2 / b2 ) + (z 2 / c2 ) = 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

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.

Other Word 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.

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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.

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

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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.

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

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