Pronunciation: (im-pēr'ē-u-liz"um),[key] —n. 1. the policy of extending the rule or authority of an empire or nation over foreign countries, or of acquiring and holding colonies and dependencies.
2. advocacy of imperial interests.
3. an imperial system of government.
4. imperial government.
5. Brit.the policy of so uniting the separate parts of an empire with separate governments as to secure for certain purposes a single state.