Geological: relating to the study of the earth's physical structure and substance. Geo-synchronous: existing or occurring at the same time. Geocentric: having or representing the earth as the centre, as in former astronomical systems. Geo-stationary: (of an artificial satellite of the earth) moving in a circular geosynchronous orbit in the plane of the equator, so that it appears to be stationary in the sky above a fixed point on the surface.