ALEA; civil law. The chance of gain or loss in a contract. This chance results either from the uncertainty of the thing sold, as the effects of a succession; or from the uncertainty of the price, as when a thing is sold for an annuity, which is to be greater or less on the happening of a future event; or it sometimes arises in consequence of the uncertainty of both. 2 Duv. Dr. Civ. Fr. n. 74.