1. The act of constituting a political unity out of a number of separate states, colonies or provinces so that each member retains the management of its internal affairs
   "The federation of Australian colonies into a single nation occurred in 1901"
    
2. A union of political organizations
   "The European Union is a federation of member states";
   - confederation, confederacy
    
3. An organization formed by merging several groups or parties
   "The labour federation represented workers from various industries"

Derived forms: federations

Type of: constitution, establishment, formation, org [informal], organisation [Brit], organization, union

Encyclopedia: Federation, Action for the Republic