/ Dictionary / Index I imperium: Meaning and Definition of Find definitions for: im•pe•ri•um Pronunciation: (im-pēr'ē-um), [key] — pl. -pe•ri•a -pe•ri•ums. command; supreme power. area of dominion; sphere of control or monopoly; empire. a nation having or exerting supreme power; superpower. the right to command the force of the state in order to enforce the law. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: imperium (Thesaurus) imperishable impermanent Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language