Satellite state is a political term that refers to a country which is formally independent, but which is primarily subject to the domination of another, larger power.
A similar phrase, Puppet state is used to connote the dependence of small nations to a larger power, implying that without necessary support of the larger power the puppet state would simply collapse.
Both terms are nearly synonimous. "Puppet state", however, tends to have a much more pejorative connotation. In some contexts, it denotes a government completely dependent on a larger power, in contrast to a satellite state which, in various aspects, including economics, has a slightly greater degree of formal independence. However, the precise relationship between the two terms is not always clear; in many instances the practical meaning of the two cannot be distinguished.