el·​lip·​soid i-ˈlip-ˌsȯid How to pronounce ellipsoid (audio)
: a surface all plane sections of which are ellipses or circles
ellipsoidal adjective
or less commonly ellipsoid

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 examples are programmatically compiled from various online sources to illustrate current usage of the word 'ellipsoid.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1721, in the meaning defined above

Time Traveler
The first known use of ellipsoid was in 1721

Dictionary Entries Near ellipsoid

Cite this Entry

“Ellipsoid.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/ellipsoid. Accessed 7 Dec. 2023.

More from Merriam-Webster on ellipsoid

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!