noun (n)

• an organization formed by merging several groups or parties(noun.group)

  source: wordnet30
• a union of political organizations(noun.group)

  Synonym:
  confederacy, confederation
  

  source: wordnet30
• 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(noun.act)

  source: wordnet30
• The act of uniting in a league; confederation.(noun)

  source: webster1913