Definition of "Empire" :

noun: an eating apple that somewhat resembles a McIntosh; used as both an eating and a cooking apple

noun: a group of countries under a single authority

"The British created a great empire."

noun: a group of diverse companies under common ownership and run as a single organization

noun: a monarchy with an emperor as head of state

noun: the domain ruled by an emperor or empress; the region over which imperial dominion is exercised