imperium

< /ɪmˈpɪər i ə/, im·pe·ri·ums.

1. command; supreme power.
2. area of dominion; sphere of control or monopoly; empire.
3. a nation having or exerting supreme power; superpower.
4. Law. the right to command the force of the state in order to enforce the law.

noun plural -ria (-rɪə)

1. (in ancient Rome) the supreme power, held esp by consuls and emperors, to command and administer in military, judicial, and civil affairs
2. the right to command; supreme power
3. a less common word for empire