Communism (from Latin communis - common, universal) is a revolutionary socialist movement to create a classless, moneyless and stateless social order structured upon common ownership of the means of production, as well as a social, political and economic ideology that aims at the establishment of this social order. This movement, in its Marxist–Leninist interpretations, significantly influenced the history of the 20th century, which saw intense rivalry between the "socialist world" (socialist states ruled by communist parties) and the "western world" (countries with capitalist economies).

Marxist theory holds that pure communism or full communism is a specific stage of historical development that inevitably emerges from the development of the productive forces that leads to a superabundance of material wealth, allowing for distribution based on need and social relations based on freely associated individuals. The exact definition of communism varies, and it is often mistakenly, in general political discourse, used interchangeably with socialism; however, Marxist theory contends that socialism is just a transitional stage on the road to communism. Leninism adds to Marxism the notion of a vanguard party to lead the proletarian revolution and to secure all political power after the revolution for the working class, for the development of universal class consciousness and worker participation, in a transitional stage between capitalism and communism.