An orbit above the equator in which a satellite will take 24 hours to make one revolution of the earth, so that it appears to be in the same position in the sky at all times: stationary with respect to points on the earth’s surface. Geostationary orbits are at a distance of 40 km above the earth’s surface, in the plane of the equator. Satellites in such orbits – often referred to as GEOS – are used for broadcast of radio and TV to specific areas of the earth. See also communications satellite.