1 Capitalism - You earn according to the value of your input towards production. Equal opportunity not equal outcomes. Free enterprise and freedom to enter into private contracts.
2 Socialism - 100% taxation (essentially confiscation of production) to be distributed evenly or according to the perceived needs by the government. Everyone receive an equal share of the produce regardless of who contributed to the production of those goods and services.
3. Communism - Socialist basis where all workers essentially belong to a single labor union. The heads of the single legal party are the heads of the union. "Workers of the nation unite". Also closely related to Marxist-Leninism where the Party\union controls the commanding heights of the economy (read Lenin's Commanding Heights Speech). All means of production (especially the major industries) are owned by the Party and private enterprise is forbidden. All land, steel mills, refineries, etc.
4. National Socialism - Referred to by many as Fascism. Socialist basis where citizens are expected to contribute more to the nation than they consume. The Fatherland or Motherland is the focus with an intense appeal to national patriotism. Any groups who contribute less than they consume are forced out (exterminated in the case of Hitler) and not to be included as nationals for equal distributions of produce. First they killed the mentally ill. Then those in prison, then the gypsies, then the jews (among others). The Party determines who contributes their share and who does not.