1. The relation or union between families, contracted by marriage.

2. The union between nations, contracted by compact, treaty or league.

3. The treaty, league, or compact, which is the instrument of confederacy; sometimes perhaps the act of confederating.

4. Any union or connection of interests between persons, families, states or corporations; as, an alliance between church and state.

5. The persons or parties allied; as, men or states may secure any alliances in their power.