Unilateral contract

A contract in which only one party makes an express promise, or undertakes a performance without first securing a reciprocal agreement from the other party.

In a unilateral, or one-sided, contract, one party, known as the offeror, makes a promise in exchange for an act (or abstention from acting) by another party, known as the offeree. If the offeree acts on the offeror's promise, the offeror is legally obligated to fulfill the contract, but an offeree cannot be forced to act (or not act), because no return promise has been made to the offeror. After an offeree has performed, only one enforceable promise exists, that of the offeror.

A unilateral contract differs from a Bilateral Contract, in which the parties exchange mutual promises. Bilateral contracts are commonly used in business transactions; a sale of goods is a type of bilateral contract.

Reward offers are usually unilateral contracts. The offeror (the party offering the reward) cannot impel anyone to fulfill the reward offer. An offeree can sue for breach of contract, however, if the offeror does not provide the reward after the offeree has fulfilled the contract's requirements.

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unilateral contract n. an agreement to pay in exchange for performance, if the potential performer chooses to act. A "unilateral" contract is distinguished from a "bilateral" contract, which is an exchange of one promise for another. Example of a unilateral contract: "I will pay you $1,000 if you bring my car from Cleveland to San Francisco." Bringing the car is acceptance. The difference is normally only of academic interest. (See: contract, bilateral contract, performance, consideration)

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UNILATERAL CONTRACT, civil law. When the party to whom an engagement is made, makes no express agreement on his part, the contract is called unilateral, even in cases where the law attaches certain obligations to his acceptance. Civ. Code of Lo. art. 1758. Code Nap. 1103. A loan of money, and a loan for use, are of this kind. Poth. Obl. part 1, c. 1, s. 1, art. 2; Lee. Elemen. Sec. 781.