Federation (noun)

1. An organization or body formed by the union of smaller political entities for a common purpose, such as for defense, economic, or political purposes.
2. A group of individuals, organizations, or countries united for a common goal or purpose.

Origin:

From latin foederatio, meaning 'a covenant or treaty'.

Examples:

1. The United States is a federation of 50 states.
2. The European Union is a political and economic federation of 27 member countries.
3. The International Olympic Committee is a federation of National Olympic Committees from around the world.
4. The teachers' federation has called for a nationwide strike to protest against the proposed education reforms.
5. The federation of farmers and ranchers has been working to promote sustainable agriculture practices.