Collateral-Contract Doctrine Law and Legal Definition

Collateral-contact doctrine is a principle that states that in a dispute concerning a written contract, proof of a second agreement, usually an oral agreement, will not be excluded under the parol-evidence rule if the oral agreement is independent of and consistent with the written contract. The information in the oral agreement would not ordinarily be expected to be included in the written contract. This is also termed as collateral-agreement doctrine.