Learner's definition of SATELLITE
an object (such as a moon) that moves around a much larger planet
a machine that is sent into space and that moves around the earth, moon, sun, or a planet
◊ Satellites are used for radio, television, and other types of communication and for studying the objects they move around.
— often used before another noun
a country, organization, etc., that is controlled by a larger and more powerful country, organization, etc.