(of a satellite) in a circular equatorial orbit in which it circles the earth once per sidereal day so that it appears stationary in relation to the earth's surface
Also: geosynchronous
geostationary in American English
(ˌdʒioʊˈsteɪʃəˌnɛri)
US
adjective
designating or of a satellite or spacecraft in an orbit above the equator, revolving at a rate of speed synchronous with that of the earth's rotation so that it always stays above the same place on the earth's surface