The term imperialism

Imperialism

Imperialism, as defined by Dictionary of Human Geography, is "the creation and/or maintenance of an unequal economic, cultural, and territorial relationships, usually between states and often in the form of an empire, based on domination and subordination." The imperialism of the last 500 years,...

was used from the third quarter of the nineteenth century to describe various forms of political control by a greater power over less powerful territories or nationalities, although analytically the phenomena which it denotes may differ greatly from each other and from the "New" imperialism

New Imperialism

New Imperialism refers to the colonial expansion adopted by Europe's powers and, later, Japan and the United States, during the 19th and early 20th centuries; expansion took place from the French conquest of Algeria until World War I: approximately 1830 to 1914...

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A later usage developed in the early 20th century among Marxists

Marxism

Marxism is an economic and sociopolitical worldview and method of socioeconomic inquiry that centers upon a materialist interpretation of history, a dialectical view of social change, and an analysis and critique of the development of capitalism. Marxism was pioneered in the early to mid 19th...

, who saw "imperialism" as the economic and political dominance of "monopolistic finance capital" in the most advanced countries and its acquisition — and enforcement through the state — of control of the means (and hence the returns) of production in less developed regions.
Elements of both conceptions are present in the "New imperialism" of the late 19th and early 20th centuries.