geoid

American  

[jee-oid] / ˈdʒi ɔɪd /

noun

1. an imaginary surface that coincides with mean sea level in the ocean and its extension through the continents.

2. the geometric figure formed by this surface, an ellipsoid flattened at the poles.

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geoid British  

/ ˈdʒiːɔɪd /

noun

1. a hypothetical surface that corresponds to mean sea level and extends at the same level under the continents

2. the shape of the earth

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geoid Scientific  

/ jē′oid′ /

1. The hypothetical surface of the Earth that coincides everywhere with mean sea level and is perpendicular, at every point, to the direction of gravity. The geoid is used as a reference surface for astronomical measurements and for the accurate measurement of elevations on the Earth's surface.

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Other Word Forms

• geoidal adjective

Etymology

Origin of geoid

First recorded in 1880–85, geoid is from the Greek word geoeidḗs earthlike. See geo-, -oid

Example Sentences

Forte also claimed the computer simulations did not accurately project the actual shape of Earth as a geoid.

From Salon • Jul. 26, 2023

These plumes, along with the nearby mantle structure, are believed to form the "gravity" hole because it winds up being the lowest point in that geoid, creating its biggest gravitational anomaly.

From Salon • Jul. 26, 2023

“When the temperature anomalies causing this low geoid shift out of the present-day location,” Pal says, “the geoid low will start to dissipate.”

From Scientific American • Jun. 26, 2023

Pal says the geoid low probably took its present shape about 20 million years ago, when the plumes started to spread within the upper mantle.

From Scientific American • Jun. 26, 2023

Compared with the “spheroid of reference” the surface of the geoid is in general depressed over the oceans and raised over the great land masses.

From Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" by Various