in the civil and canon law, the relation contracted between two persons or two families by marriage.

Alliance is also used for a treaty entered into by sovereign princes and states, for their mutual safety and defence.—In this sense, alliances may be distinguished into such as are offensive, whereby the contracting parties oblige themselves jointly to attack some other power; and into defensive ones, whereby they bind themselves to stand by and defend each other in case they are attacked by others.—Alliance, with the ancient Romans, though a sort of servitude, was much coveted. Ariarathes, we are told by Polybius, offered a sacrifice to the gods by way of thanksgiving for having obtained this alliance. The reason was, that thenceforward people were sure not to receive any injuries except from them.—There were different sorts of alliances: some only united to them by a participation of the privileges of Romans, as the Latini and Hernici; others by their very foundation, as the colonies; others by the benefactions they received from them, as Mafinissa, Eumenes, and Attalus, who owed their kingdoms to Rome; others by free treaties, which last by a long alliance became subjects, as the kings of Bithynia, Cappadocia, Egypt, and most of the cities of Greece; lastly, others by compulsive treaties, and the law of subjection, as Philip and Antiochus. For they never granted peace to an enemy, without making an alliance with him; that is, they never subdued any people without using it as a means of subduing others.

The forms or ceremonies of alliances have been various in different ages and countries. Among us, signing and swearing, sometimes at the altar, are the chief; anciently eating and drinking together, chiefly offering sacrifices together, were the customary rite of ratifying an alliance. Among the Jews and Chaldeans, heifers of calves; among the Greeks, bulls or goats; and among the Romans, hogs were sacrificed on this occasion. Among the ancient Arabs, alliances were confirmed by drawing blood out of the palms of the hands of the two contracting princes with a sharp stone, dipping therein a piece of their garments, and therewith smearing seven stones, at the same time invoking the gods Vrotalt and Aljlat, i.e., according to Herodotus, Bacchus and Urania. Among the people of Cholchis, the confirmation of alliances is said to be effected by one of the princes offering his wife's breafsts to the other to suck, which he was obliged to do till there issued blood.

a figurative sense, is applied to any kind of union or connection; thus we say, there is an alliance between the church and state.