Coalition
group formed of people, factions, states, political parties, militaries, or other parties agree to work together, often temporarily, in a partnership to achieve a common goal
A coalition is an alliance, where the members work together.

The English Wiktionary has a dictionary definition (meanings of a word) for: coalition
Politics and government change
A coalition government, in a parliamentary system, is a government made from a coalition of parties. This means the union of different political parties or groups for a purpose, usually for a short time.
In international relations, a coalition can be a group of nations united for a specific purpose, such as fighting a war.