aleatory contract

Type of contract (1) whose execution or performance depends on a contingency or an uncertain (random) event beyond the control of either party, and/or (2) under which the sums paid by the parties to each other are unequal. Most insurance policies are aleatory contracts because the insured may collect a large amount or nothing in return for the premiums paid. From French 'alea,' a game of dice. See also unilateral contract.