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. It is now used as the title of the monarch of some single countries,, as lately in Brazil, and some composite states, as Germany and Austria-Hungary, and by the king of England as “Emperor of India.”
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 is the case with the German empire at the present day.