noun (n)

• an organization of people (or countries) involved in a pact or treaty(noun.group)

  Synonym:
  alignment, alinement, alliance
  Antonym:
  nonalignment, nonalinement
  

  source: wordnet30
• the state of being combined into one body(noun.state)

  Synonym:
  fusion
  

  source: wordnet30
• the union of diverse things into one body or form or group; the growing together of parts(noun.act)

  Synonym:
  coalescence, coalescency, concretion, conglutination
  

  source: wordnet30
• The act of coalescing; union into a body or mass, as of separate bodies or parts; as, a coalition of atoms.(noun)

  source: webster1913