Imperijalizam je održavanje i širenje moći nad stranim nacijama, posebno kroz ekspanzionizam, koristeći i tvrdu moć (vojnu i ekonomsku moć) i meku moć (diplomatsku moć i kulturni imperijalizam). Imperijalizam se fokusira na uspostavljanje ili održavanje hegemonije i manje ili više formalnog carstva.[3][4][5] Iako je povezan s konceptom kolonijalizma, imperijalizam je poseban koncept koji se može primijeniti na druge oblike ekspanzije i mnoge oblike vladavine.[6]
state policy, practice, or advocacy of extending power and dominion, especially by direct territorial acquisition or by gaining political and economic control of other areas. Because it always involves the use of power, whether military or economic or some subtler form, imperialism has often been considered morally reprehensible, and the term is frequently employed in international propaganda to denounce and discredit an opponent's foreign policy.
... the policy of extending the rule or authority of an empire or nation over foreign countries, or of acquiring and holding colonies and dependencies ...
In its most general sense, imperialism refers to the formation of an empire, and, as such, has been an aspect of all periods of history in which one nation has extended its domination over one or several neighbouring nations.