Referring to the solar system when it is regarded as having the Earth as its center: From a geocentric point of view, many people think of the Earth as being the center of all matter.

A geocentric theory or belief maintains that the Earth and its inhabitants are the center of existence.

A certain geocentric location of the Earth is thought to be a reference point for measurement.

1. In astronomy, geocentric coordinates: A geocentric coordinate system is an arrangement of celestial coordinates located with respect to the center of the Earth.
2. In cartography, a set of map coordinates which define the position of a point with respect to the center of the Earth: In class, Mr. Smart asked the students to study the geocentric coordinate system and to measure the different geocentric distances from given points.

In cartography, or maps, the plane through the center of the Earth: The geocentric horizon is parallel to the topocentric (a point on the surface of the Earth) horizon:

1. In astronomy, the angular distance in degrees which a celestial object lies north or south of the Earth's equator: The students in Mr. Green's class were asked to locate the geocentric latitude of the planet he assigned them.
2. In geodesy, the angle formed with the major axis of the ellipse (stretched circle with slightly longer, flatter sides) by the radius vector (magnitude and a direction) from the center of the ellipse to the given point: The geocentric latitude is the position on the Earth's surface, the angle between the place of the equator and the center of the Earth.

The angular distance in degrees that a celestial object lies east or west of Greenwich Meridian, or the meridian passing through Greenwich (Greater London borough on the Thames in England: The geocentric longitude was internationally adopted as the Earth's zero of longitude in 1884.

The change in an astronomical object's apparent position: A geocentric parallax is caused by the change in the observer's earthly position because of the motion of the Earth during the day.

In history, the ancient belief that the sun and other bodies of the solar system revolve around the Earth: The geocentric theory was stated in detail by Ptolemy about 140 A.D. and later replaced by the heliocentric theory of Copernicus.

The point at which a line from the center of the Earth through a point on its surface meets the celestial sphere: The geocentric zenith Mr. Tall showed his class was viewed on a model of the universe.