Definition: an authoritative Prātiśākhya work attributed to Śaunaka the teacher of Āśvalāyana, belonging prominently to the Sakala and the Bāṣkala Śakhās of the Ṛgveda. it is widely known by the name Ṛk-Prātiśākhya. It is a metrical composition divided into . 18 chapters called Paṭalas, giving special directions for the proper pronunciation, recitation and preservation of the Ṛksaṁhita by laying down general rules on accents and euphonic combinations and mentioning phonetic and metrical peculiarities. It has got a masterly commentary written by Uvvaṭa.