The facts outside a contractual agreement that may be used to interpret the agreement.
Contract law prescribes a complicated set of tests—termed the parol evidence rule—by which the admissibility of parol evidence in discerning the contracting parties’ intent may be decided. The admissibility of parol evidence is extremely limited in cases of an integrated agreement—a contract whose provisions make it clear that it contains within itself all the terms of the agreement between the parties.
The “entire contract” clause found in many insurance policies is intended to make those policies integrated agreements and prevent the use of parol evidence in interpreting them.