The last veda called the Atharva Veda is a collection of magic spells and charms to ward off the evil spirits and diseases. It is considered a non-Aryan work and is the latest addition to the Vedas in later Vedic age.
Sabha or Mahasabha during the Chola empie referred to the exclusive assembly of Brahmans/gatherings of the adult male members in the agraharas, that is, the rent free brahmadeya villages. These assemblies enjoyed a large measure of autonomy.