The Collaborative International Dictionary of English v.0.48:

nationalize \na"tion*al*ize\, v. t. [imp. & p. p.
   Nationalized; p. pr. & vb. n. Nationalizing.] [Cf. F.
   nationaliser.]
   1. To make national; to make a nation of; to endow with the
      character and habits of a nation, or the peculiar
      sentiments and attachment of citizens of a nation.
      [1913 Webster]

   2. To change ownership of (a business, a property) from
      private ownership to state ownership or control; as, to
      nationalize the steel industry.
      [PJC]

WordNet (r) 3.0 (2006):

nationalize
    v 1: put under state control or ownership; "Mitterand
         nationalized the banks" [syn: nationalize, nationalise]
         [ant: denationalise, denationalize]
    2: make national in character or scope; "His heroic deeds were
       nationalized by the press" [syn: nationalize,
       nationalise]

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "nationalize":
   annex, attach, collectivize, commandeer, communalize, communize,
   confiscate, democratize, distrain, expropriate, garnish, impound,
   impress, levy, politicize, press, replevin, replevy, republicanize,
   sequester, sequestrate, socialize