A geostationary orbit.
An orbit of a satellite around a rotating body, such that one orbit is completed in the time it takes for the body to make one revolution on its own axis. From the viewpoint of the rotating body (such as Earth), a satellite in synchronous orbit appears to hover over a single position or else to sweep back and forth once per revolution along a single line in the sky. Synchronous orbit is sometimes used synonymously with geostationary orbit, although the two terms are identical only if the synchronous orbit is in the equatorial plane (when the satellite appears to hover motionless over the rotating body). Artificial satellites in synchronous orbits are commonly used in telecommunications, due to their relatively stable overhead position with respect to the Earth's surface.