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.

---

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

---

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.

---

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

As a result, if all of Earth's ocean existed under gravity without factors like wind and tides, the planet would more closely resemble a geoid: Imagine a golf ball melted to the point where some of its dimples expanded and other collapsed, and you have a good approximation a geoid's appearance.

From Salon

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

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

From Salon

This produces an exaggerated visualization of our planet’s gravitational high and low spots called the global geoid.

From Scientific American

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