The sanskrit word “gnana” or “vidhya” means knowledge or intellect. He plays Manikka Veena and sits under a banyan tree like Dhakshinamoorthi. He blesses us with knowledge & intelligence, and hence is the name.
He is considered like lord Shiva of all three worlds. There are references of this Sāstha in a purana - “Aakasa Bhairava Kalpam.” Sree Dharma Sāstha temple in Thiruvullakavu is considered as THE ABODE OF WISDOM even though Sāstha is not in the Dhakshinamoorthy form in this temple. There is an idol of Sri Vidhya Sāstha in Veda Nayaga Sāstha temple at Vedikarampalayam, Salem.