federation
1 of 1noun/ˌfɛdəˈreɪʃən/
Forms:federations
1
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
2
a union of political organizations
Synonyms:
3
the union of organizations, regions, countries, etc. to form a larger organization or government