The subject of this study is the most famous and most frequently used metarule of the Sanskrit grammar "Aṣṭādhyāyī" compiled by the ancient Indian linguist Pāṇini. This metarule is called "bahiraṅgaparibhāṣā" and serves to determine the correct sequence of grammatical operations prescribed in the "Aṣṭādhyāyī". The material of the study are various interpretation of the bahiraṅgaparibhāṣā in Sanskrit commentaries on the "Aṣṭādhyāyī", as well as in the collections of metarules compiled by Sanskrit grammarians. The purpose of the work is to acquaint the Russian-speaking reader with the most important interpretative tool of the grammar of Panini — bahiraṅgaparibhāṣā, as well as with the history of the interpretation of this metarule in Sanskrit grammatical literature. The research method is a comparative analysis of Sanskrit primary sources containing interpretations of the bahiraṅgaparibhāṣā. For the first time in the Russian-language literature, a detailed analysis of the bahiraṅgaparibhāṣā has been made. The history of the origin of this metarule and its interpretation by Sanskrit grammarians has been studied. The signs of acquaintance of Panini with bahiraṅgaparibhāṣā are investigated. It is shown that, despite the widespread use of this metarule, the mechanism of its application was not explicitly described until the XVIII century AD, when this problem was completely solved by the grammarian Nāgojībhaṭṭa in his work "Paribhāṣenduśekhara". It is established that one of the main achievements of Nāgojībhaṭṭa was the strict definition of the concepts of antaraṅga and bahiraṅga — the most important elements of the statement of bahiraṅgaparibhāṣā.