Contracts
Parol Evidence Rule
Definition
The parol evidence rule bars the introduction of extrinsic evidence — oral or written statements made before or at the time of contracting — to contradict, modify, or vary the terms of a fully integrated written agreement. However, parol evidence may be admitted to explain ambiguous terms, prove fraud or duress, establish a condition precedent, or show that the writing was not intended as a complete integration. The UCC takes a more liberal approach in trade usage and course of dealing contexts.
Example
A buyer and seller sign a written contract for 100 tons of steel. The buyer may not introduce testimony that they orally agreed to 200 tons if the contract is fully integrated.