Imperium is a
Latin word which, in a broad sense, translates roughly as '
power to command'. In
ancient Rome, different kinds of power or
authority were distinguished by different terms.
Imperium referred to the ability of an individual to command the military. It is not to be confused with
auctoritas or
potestas, different and generally inferior types of power in the
Roman Republic and
Empire. Primarily used to refer to the power that is wielded, in greater or lesser degree, by an individual to whom it is delegated, the term could also be used with a geographical connotation, designating the territorial limits of that
imperium. Individuals given such power were referred to as curule
magistrates or
promagistrates. These included the curule
aedile, the
praetor, the
censor, the
consul, the
magister equitum, and the
dictator.