The highest spiritual status of a soul, Atmik Awastha, that a person can achieve.  The practice of Sat makes a soul merge in the Sat and the one who becomes one with Sat becomes a Braham Roop.  By doing so it means that such a soul becomes a source of the Braham Gyan.  Becomes a source of Sat, a source of Amrit for others and is therefore called a Braham Gyani.