el·​lip·​soid | \ i-ˈlip-ˌsȯid How to pronounce ellipsoid (audio) , e- \

Definition of ellipsoid

: a surface all plane sections of which are ellipses or circles

Other Words from ellipsoid

ellipsoidal \ i-​ˌlip-​ˈsȯi-​dᵊl How to pronounce ellipsoid (audio) , (ˌ)e-​ \ or less commonly ellipsoid adjective

Examples of ellipsoid in a Sentence

Recent Examples on the Web When the geoid is above the ellipsoid, the difference is subtracted. Freddie Wilkinson, National Geographic, 28 Sep. 2020 Again, by elementary optics and geometry, light rays originating at one focus of a hollow reflective ellipsoid are reflected to the other focus by its inside surface. Quanta Magazine, 1 Apr. 2020 The earth is slightly thicker in the equator, making it an ellipsoid, technically. Caroline Delbert, Popular Mechanics, 17 Dec. 2019 From radar observations, Psyche the asteroid appears ellipsoid in shape, about as wide as Massachusetts. Kenneth Chang, New York Times, 6 Jan. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ellipsoid.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of ellipsoid

1721, in the meaning defined above

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The first known use of ellipsoid was in 1721

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ellipsoidal spotlight

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Cite this Entry

“Ellipsoid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ellipsoid. Accessed 25 Jun. 2022.

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More from Merriam-Webster on ellipsoid

Britannica.com: Encyclopedia article about ellipsoid


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