GEO - technical definition

At a position approximately 22,235 statute miles (35,784 km) above the equator, a satellite in orbit is in synchronization with the revolution of the earth. In other words, the satellite rotates around the earth at the same speed as the Earth rotates on its axis. As a result, the satellite maintains its relative position over the same spot of the earth's surface and is kept from wandering by tidal forces. At that altitude, the centrifugal force acting to fling the satellite away from the Earth is equal to, and therefore cancels out, the centripetal force of gravity acting to pull the satellite into the Earth. Therefore, the satellite maintains its vertical distance, or altitude. As a GEO maintains a stable position in the heavens, transmit and receive earth stations can be pointed to fixed coordinates to establish a communications link, secure in the knowledge that the satellite will be there. A Geosynchronous Earth Orbiting (GEO) satellite is also known as a Fixed Satellite System (FSS) because of its fixed positions relative to the Earth's surface. Neither a Low Earth Orbit (LEO) nor a Medium Earth Orbit (MEO) offers this level of stability. See also FSS, LEO, MEO, and satellite.