Source : Webster's Revised Unabridged Dictionary (1913)

Federation \Fed`er*a"tion\, n. [Cf. F. f['e]d['e]ration.]
   1. The act of uniting in a league; confederation.

   2. A league; a confederacy; a federal or confederated
      government. --Burke.

Source : WordNet®

federation
     n 1: an organization formed by merging several groups or parties
     2: a union of political organizations [syn: {confederation}, {confederacy}]
     3: the act of constituting a political unity out of a number of
        separate states or colonies or provinces so that each
        member retains the management of its internal affairs