term:

Four Corners

four corners n pl

: the contents of a document as interpreted without reference to or consideration of outside information
: the face of a document [any evidence offered…must appear within the four corners of the will "Crump's Estate v. Freeman, 614 P.2d 1096 (1980)"]

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.