नश्चापदान्तस्य झलि

Operational rule vidhi

In the context of संहिता, a मकार and a नकार which do not occur at the end of a पद are converted to अनुस्वार when followed by a झल् letter.

Word by word (padaccheda)

Target नः ṣaṣṭhī · ekavacanaIndeclinable च avyayaTarget अपदान्तस्य ṣaṣṭhī · ekavacanaRight context saptamī · ekavacana

Target Ṣaṣṭhī (6th case): names what gets replaced, "in place of X" (1.1.49 षष्ठी स्थानेयोगा).
Indeclinable An avyaya such as च "and", वा "optionally", न "not".
Right context Saptamī (7th case): "when X follows", the operation applies to what precedes (1.1.66 तस्मिन्निति निर्दिष्टे पूर्वस्य). Also a condition or domain ("in the sense of").

Dotted words are technical terms, dashed ones pratyāhāras (names for classes of sounds or affixes). Hover or tap one to see its card.

Full reading

नः च अपदान्तस्य

Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.

Commentary

The अनुस्वार is substituted for न् and not म् final in a word, before all consonants, with the exception
Thus पयांसि, यशांसि, सर्पींषि, धनूंषि with न् 7.1.72; and आक्रंस्यते, आविक्रंस्यते, अधिजिगांसते with म् ॥

Why do we say 'not final in a Pada'? Observe राजन् भुङ्क्ष्व ॥ Why do we say 'before a झल् consonant'? See रम्यते, गम्यते ॥

Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.