/,fedə'reɪʃn; ,fɛdə`reʃən/
n
1 [C] union of states in which individual states retain control of many internal matters but in which foreign affairs, defence, etc are the responsibility of the central (federal) government 联邦.
2 [C] similarly organized union of societies, trade unions, etc （社团、工会等的）联合会.
3 [U] action of forming a federation 结成联邦政府; 联盟.

n
[C]
a group of organizations, clubs, or people that have joined together to form a single group
　the National Federation of Women's Institutes
[C]
a group of states that have joined together to form a single group
　the Russian Federation
[U]
when groups of people, states etc join together to form a larger group