Mahabhashya (Sanskrit: महाभाष्य, IAST: Mahābhāṣya, IPA: [mɐɦaːbʱaːʂjɐ], "Great Commentary"), attributed to Patañjali, is a commentary on selected rules of Sanskrit grammar from Pāṇini's treatise, the Aṣṭādhyāyī, as well as Kātyāyana's Vārttika-sūtra, an elaboration of Pāṇini's grammar.
The system thus established is extremely detailed as to shiksha (phonology, including accent) and vyakarana (grammar and morphology).
But the main contributions of Patañjali lies in the treatment of the principles of grammar enunciated by him.
[7] Kāśika-vritti by Jayāditya and Vāmana (mentioned by Itsing) included viewpoints of other grammarians also which did not conform to Patañjali's views.
The Mahābhāṣya is divided into eighty five sections called āhnika consisting of subject matter of one day's study each.