वाऽवसाने

Operational rule vidhi

A झल् letter is optionally converted to a corresponding चर् -letter when it is not followed by any other letter.

Word by word (padaccheda)

Indeclinable वा avyayaRight context saptamī · ekavacana

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

वा

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

Commentary

The चर् is optionally the substitute of a झल् that occurs in a Pause.
The words झलां चर् is understood in the sutra. A sonant or a surd non-aspirate may stand as final in a Pause: but not an aspirate consonant. By 8.2.39, a non-aspirate sonant can only stand in a final position. This ordains that a non-aspirate surd may also stand as the final, when there is Pause. Thus वाक् or वाग्, त्वक् or त्वग्, श्वलिट् or श्वलिड्, त्रिष्टुप् or त्रिष्टुब् ॥

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