Generally speaking socialism and communism are synonymous.

Socialism and communism are both economic systems in which the public owns the means of production. The means of production include the raw materials and means of labor, such as machines and tools, used in production processes. Under both systems the state also engages in centralized planning; in a planned or command economy, business activities and resource allocation are controlled by the state, ostensibly for the greater good.[1] Socialism advocates public ownership of property and natural resources rather than private ownership. The socialist system of government values cooperation over the competitiveness of a free market economy. Socialists believe that all people in society contribute to the production of goods and services and that those goods should be shared equally. This differs from the capitalist system in which individual efforts trump the collective and the free market determines the distribution of goods. Examples of socialist policies include a living wage, free higher education and universal health care. Advocates of socialism believe that capitalism creates vast inequality and that it ultimately leads to imperialism, a hyper-form of capitalism.[3] The communist doctrine differs from the socialist worldview because communism calls not only for public ownership of property and natural resources, but also for the means of production of goods and services. Karl Marx argued that capitalism, with its strict adherence to free market principles, divided people because of competition. He believed communism was the solution. According to Marx, communism would give people a chance to develop into their very best. He concluded that communism was a natural progression from socialism and would occur in two stages. First, the working class would gain control of society and push the ownership class out. Second, society would evolve into a classless one without government. According to Britannica.com, Marx and Friedrich Engels defined communists in their "Communist Manifesto" as, "The most advanced and resolute section of the working class which parties every country, that section which pushes forward all others."[4] Among the etymological source quotes in the Oxford English Dictionary you find: "Forster Diary 11 May in T. W. Reid Life (1888) .... I learn that the great distinction between communism and socialism is that the latter believes in payment according to work done and the former does not".[5][6] In other words, socialism is "...to each according to deed" as opposed to communism's "...to each according to need". Remuneration for labour-time is the essential characteristic of socialism (see Parecon, for e.g.). Or, as communists since the time of Malatesta and Kropotikin have called it, "the Wage System". The primary difference between communism and socialism is, given that a classless society based on the wage system is impossible, is that the former, however difficult to achieve, is at least possible. Whereas socialism is not. Forster is not the only source, by any means. It's in J.S.Mill's "Principles of Political Economy" for e.g. Using definitions from thesauri is rather pointless, as the heories of Marxism are too complex to be defined in a few sentences. In order to understand both of these concepts, one must study deeper into socialist and communist theory. References: [1]http://classroom.synonym.com... [3]http://www.britannica.com... [4]http://www.britannica.com... [5]http://writing.upenn.edu... (1.a.1848) [6]http://struggle.ws...