The word geostationary comes from the actuality that a type of satellite that appears almost stationary in the sky when seen by an observer from the ground.
A geostationary satellite is an earth-orbiting satellite, set at a height of around 35,800 km (22,300 miles) directly over the equator which revolves in the same direction and at the same rate the earth rotates (from west to east).
Role of a geostationary satellite: The fundamental use of geostationary satellites can be seen as follows:
For the launching rockets in space.
For telecommunication purposes.
In the study of the upper region of the atmosphere.