Definition of Four comers rule
Under "four corners rule”, intention of parties, especially that of grantor, is to be gathered from instrument as a whole and not from isolated parts thereof. Davis v. Andrews, Tex.Civ.App., 361 S.W.2d 419, 423.
That's the definition of Four comers rule in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.