com•mu•nism (käm´yōniz´əm, -yə-) n.

 1 any theory or system characterized by the ownership or sharing of all property by the community as a whole
 2 [often C-]
 a) as envisioned by Marx, a future condition of mankind achieved after the revolutionary overthrow of capitalism and a transitional stage of socialism, and characterized by a largely self-regulating society whose members have renounced private property and personal wealth, national identity, social-class differences, etc.
 b) a political system that advances revolutionary principles for achieving this condition, either as formulated by Marx or as modified by Lenin, Stalin, Mao Tse-tung, etc., characterized by a single ruling party, centralized economic planning, the curtailment of individual liberties, etc.
 3 loosely, leftist or socialist ideas, activity, etc.