External evidence, or that which is not contained in the body of an agreement, contract, and the like. 2. It is a general rule that extrinsic evidence cannot be admitted to contradict, explain, vary or change the terms of a contract or of a will, except in a latent ambiguity, or to rebut a resulting trust. 3. Typically refers to evidence surrounding the interpretation of a contract. This is evidence which is not contained within the contract itself but is evidence to explain the meaning or intent of the parties or which further explains an ambiguity in the contract. The evidence is admissible where an ambiguity exists in a contract in order to explain its meaning.