alliance

The state of being allied.

“matrimonial alliances; an alliance between church and state, or between two countries”

The act of allying or uniting.

A union or connection of interests between families, states, parties, etc., especially between families by marriage and states by compact, treaty, or league.

Any union resembling that of families or states; union by relationship in qualities; affinity.

(with the definite article) The persons or parties allied.

To connect or unite by alliance; to ally.