The Collaborative International Dictionary of English v.0.48:

Confederation \Con*fed`er*a"tion\, n. [L. confoederatio: cf. F.
   conf['e]d['e]ration.]
   1. The act of confederating; a league; a compact for mutual
      support; alliance, particularly of princes, nations, or
      states.
      [1913 Webster]

            The three princes enter into some strict league and
            confederation among themselves.       --Bacon.
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            This was no less than a political confederation of
            the colonies of New England.          --Palfrey.
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   2. The parties that are confederated, considered as a unit; a
      confederacy.
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   Articles of confederation. See under Article.
      [1913 Webster]

WordNet (r) 3.0 (2006):

confederation
    n 1: the state of being allied or confederated [syn: alliance,
         confederation]
    2: a union of political organizations [syn: confederation,
       confederacy, federation]
    3: the act of forming an alliance or confederation [syn:
       confederation, alliance]