An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Of, relating to, or suggestive of an empire or a sovereign, especially an emperor or empress (TheFreeDictionary).

Adjective of → empire.

1) The extension of a nation's authority by territorial acquisition or by the establishment of economic and political dominance over other nations.
2) A political doctrine or system promoting such extension of authority (TheFreeDictionary.com).

→ imperial; → -ism.