The Collaborative International Dictionary of English v.0.48:

Socialism \So"cial*ism\, n. [Cf. F. socialisme.]
   A theory or system of social reform which contemplates a
   complete reconstruction of society, with a more just and
   equitable distribution of property and labor. In popular
   usage, the term is often employed to indicate any lawless,
   revolutionary social scheme. See Communism, Fourierism,
   Saint-Simonianism, forms of socialism.
   [1913 Webster]

         [Socialism] was first applied in England to Owen's
         theory of social reconstruction, and in France to those
         also of St. Simon and Fourier . . . The word, however,
         is used with a great variety of meaning, . . . even by
         economists and learned critics. The general tendency is
         to regard as socialistic any interference undertaken by
         society on behalf of the poor, . . . radical social
         reform which disturbs the present system of private
         property . . . The tendency of the present socialism is
         more and more to ally itself with the most advanced
         democracy.                               --Encyc. Brit.
   [1913 Webster]

         We certainly want a true history of socialism, meaning
         by that a history of every systematic attempt to
         provide a new social existence for the mass of the
         workers.                                 --F. Harrison.
   [1913 Webster]

   Socialism of the chair [G. katheder socialismus], a term
      applied about 1872, at first in ridicule, to a group of
      German political economists who advocated state aid for
      the betterment of the working classes.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

socialism
    n 1: a political theory advocating state ownership of industry
    2: an economic system based on state ownership of capital [syn:
       socialism, socialist economy] [ant: capitalism,
       capitalist economy]

Moby Thesaurus II by Grady Ward, 1.0:

50 Moby Thesaurus words for "socialism":
   Fabian socialism, Fabianism, Marxian socialism, Marxism, Nazism,
   Saint-Simonism, centralism, collective farm, collective ownership,
   collectivism, collectivity, collegiality, common ownership,
   communal effort, communion, communism, community,
   constitutionalism, cooperation, cooperative society, democracy,
   democratism, fascism, federalism, feudalism, feudality,
   governmentalism, guild socialism, imperialism, kibbutz, kolkhoz,
   monarchism, national socialism, nationalization, neofascism,
   parliamentarianism, parliamentarism, phalansterism, pluralism,
   political principles, profit sharing, public ownership,
   republicanism, royalism, sharecropping, state ownership,
   state socialism, statism, town meeting, utopian socialism