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The hypothetical surface of the earth that coincides everywhere with mean sea level.

[German, from Greek geoeidēs, earthlike : , earth + -oeidēs, -oid.]

ge·oid′al (-oid′l) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


1. (Geological Science) a hypothetical surface that corresponds to mean sea level and extends at the same level under the continents
2. (Physical Geography) the shape of the earth
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈdʒi ɔɪd)

an imaginary surface that coincides with mean sea level in the ocean and its extension through the continents.
[1880–85; < Greek geoeidḗs earthlike. See geo-, -oid]
ge•oi′dal, adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
References in periodicals archive ?
Gravity anomalies are mainly used for (1) determination of the geoid, (2) interpolation and geophysical extrapolation of gravity, (3) geological mapping and exploration for natural resources, and (4) investigation of the Earth's crust.
Presentation at Nordic Geodetic Commission Working Group of Geoid and Height Systems meeting, Tallinn, 12-18 March 2016.
The results show that the current relative accuracy of the most accurate geoid models is better than 10 mm.
Keywords:Global geopotential model, GNSS/levelling, Geoid undulations, Orthometric and ellipsoidal heights.
On local and national scale, gravity data have been applied to gravimetric geoid modelling (Maasik 1952; Vermeer 1994; Jurgenson 1998; Ellmann 2001; Mardla et al.
Despite the fact that Torge in 1999 (Torge, 1999) had used these methods, he showed that the difference between surfaces of reference (reference ellipsoid and geoid) did not effect on the result of determined velocity of vertical movements of the Earth's surface.
In this study, the mean elevations of various hemispheres were calculated or estimated from satellite geoid data.
Mean Sea Level (MSL) is an approximation of the geoid based on tidal measurement at individual locations, and is used extensively for topographic and engineering surveying and mapping.
The microarray data were deposited in the NCBI GEO database (GEOID: GSE99868) and validated by analysing the expression of 7 different genes by RT-qPCR as described below.
He said the new OS "geoid model" meant heights taken with GPS equipment would alter "not by a great amount, but in the case of Calf Top, by an amount that makes all the difference".