imperator (n.) Look up imperator at Dictionary.com
"absolute ruler," 1580s, from Latin imperator "commander-in-chief, leader, master," agent noun from stem of imperare "to command" (see imperative (adj.)). In the Roman republic, a holder of military command during active service, also a title bestowed on victorious generals; in the Roman Empire, the emperor as commander-in-chief of the armies. Related: Imperatorial.