Imperium in imperio, meaning "an empire within an empire", is a phrase commonly used to describe a situation where a small group or organization possesses a significant influence or power within a larger entity. Synonyms for this term include "state within a state", "shadow government", "parallel government", "deep state", and "secret society". These terms describe the notion of a covert, powerful group working behind the scenes to make decisions or influence policy. While imperium in imperio suggests a level of official secrecy and organizational structure, these synonyms are more commonly used in geopolitical and conspiracy theories contexts.