From the Merriam-Webster Dictionary:
socialism
noun (Concise Encyclopedia)
System of social organization in which private property and the distribution of income are subject to social control; also, the political movements aimed at putting that system into practice. Because “social control” may be interpreted in widely diverging ways, socialism ranges from statist to libertarian, from Marxist to liberal. The term was first used to describe the doctrines of Charles Fourier, Henri de Saint-Simon, and Robert Owen, who emphasized noncoercive communities of people working noncompetitively for the spiritual and physical well-being of all (see utopian socialism). Karl Marx and Friedrich Engels, seeing socialism as a transition state between capitalism and communism, appropriated what they found useful in socialist movements to develop their “scientific socialism.” In the 20th century, the Soviet Union was the principal model of strictly centralized socialism, while Sweden and Denmark were well-known for their noncommunist socialism. See also collectivism, communitarianism, social democracy.