What type of contract involves a party accepting an obligation without assuming a reciprocal obligation?

A unilateral contract is one where one party makes a promise or accepts an obligation without requiring a corresponding commitment or promise from the other party. This means that one party is bound to fulfill their obligation, while the other party is not necessarily obligated to perform any action or provide any consideration in return.

For example, if someone offers a reward for the return of a lost item, they are making a unilateral contract. The person who finds and returns the item is not obligated to do so, but the one offering the reward has committed to paying the specified amount upon completion of the task.

This form of contract is distinct from onerous contracts, which involve mutual obligations where both parties exchange something of value. Gratuitous contracts also involve no exchange of consideration, but they often indicate an intention to give without expecting anything in return, which is not always the case in unilateral contracts. Aleatory contracts depend on uncertain events, meaning that performance is contingent upon an event happening, which differentiates them from the straightforward promise found in unilateral contracts.