The parol evidence rule is a rule in the Anglo-American common law that governs what kinds of evidence parties to a contract dispute can introduce when trying to determine the specific terms of a contract. The rule also prevents parties who have reduced their agreement to a final written document from later introducing other evidence, such as the content of oral discussions from earlier in the negotiation process, as evidence of a different intent as to the terms of the contract. The rule provides that "extrinsic evidence is inadmissible to vary a written contract". The term "parol" derives from the Anglo-Norman French parol or parole, meaning "word of mouth" or "verbal", and in medieval times referred to oral pleadings in a court case.