Definition of Emperor
The title of the sovereign ruler of an empire. This designation was adopted by the rulers of the Roman world after the decay of the republic, and was assumed by those who claimed to be their successors in the “Holy Roman Empire,” as also by Napoleon. The sovereigns of Japan and Morocco are often, though with Uttle propriety, called emperors. In western speech the former sovereigns of Turkey and China were called emperors.
The title “emperor” seems to denote a power and dignity superior to that of a “king.” It appears to be the appropriate style of the executive head of a federal government, constructed on the monarchial principle, and comprising in its organization several distinct kingdoms or other quasi sovereign states; as was the case with the German empire from 1871 to 1918. The proper meaning of emperor is the chief of a confederation of states of which kings are members. In general, an emperor is the holder of a sovereignty extending over conquered or confederated peoples, a king is ruler of a single people.
That's the definition of Emperor in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.
