Which term describes a contract where performance depends upon an uncertain future event?

The term that describes a contract where performance depends upon an uncertain future event is "Aleatory." This type of contract includes elements of chance or risk, meaning that the obligations of one or both parties may not be executed unless a specific event occurs. For instance, in an insurance policy, the insurer's obligation to pay claims arises only when an insured event, such as a car accident or property damage, happens. The nature of aleatory contracts is such that the outcomes are uncertain, which is different from other types of contracts where performance is generally guaranteed regardless of external conditions.

In contrast, a conditional contract relies on a specific condition or event occurring rather than introducing the element of risk associated with its uncertain nature. Unilateral contracts involve a promise from one party contingent on an act by another party, and bilateral contracts consist of mutual promises made by both parties. Each of these other contract types has distinct characteristics that set them apart from aleatory contracts, which are uniquely defined by their reliance on uncertain future events.