Imperialism is maintaining or extending power over foreign nations, particularly through expansionism, employing both hard power (military and economic power) and soft power (diplomatic power and cultural imperialism). Imperialism focuses on establishing or maintaining hegemony and a more or less formal empire.[3][4][5] While related to the concepts of colonialism, imperialism is a distinct concept that can apply to other forms of expansion and many forms of government.[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.