8.3.8
उभयथर्क्षु
Operational rule vidhi
In the context of संहिता and in the vedas, when a पदान्त नकार is followed by a letter from छव् प्रत्याहार, which in turn is followed by a letter from अम् प्रत्याहार, then the नकार is optionally converted to रुँ.
Word by word (padaccheda)
Indeclinable उभयथा avyayaRight context ऋक्षु saptamī · bahuvacana
- 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
उभयथा ऋक्षु
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
Commentary
In both ways in the ऋग् verses.
This ordains an option to the last sutra, by which the रु substitution was compulsory. A word ending in म् followed by a letter of छव् class, which itself is followed by अम्, changes its final म् to र् optionally in the Rig Veda. Sometimes there is र् and sometimes म् ॥ Thus तस्मिन् त्वा दधाति or तस्मिँस् त्वा दधाति; पशूँस्ताँश्चक्रे ॥
Why do we say "in the Rig verses". No option is allowed here ताँस्त्व खाद सुखादिताम् ॥
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.