7.1.102
उदोष्ठ्यपूर्वस्य
Operational rule vidhi
If a verb root ends in a दीर्घ ॠकार before which an ओष्ठ्य letter is present, the ॠकार of that verb root is converted to उकार.
Word by word (padaccheda)
Substitute / term उत् prathamā · ekavacanaTarget ओष्ठ्यपूर्वस्य ṣaṣṭhī · ekavacana
- Substitute / term Prathamā (1st case): in operational rules, the substitute or the thing introduced; in definitions, the term or its referent.
- Target Ṣaṣṭhī (6th case): names what gets replaced, "in place of X" (1.1.49 षष्ठी स्थानेयोगा).
Dotted words are technical terms. Hover or tap one to see its card.
Full reading
उत् ओष्ठ्यपूर्वस्य
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
ओष्ठ्यपूर्वस्य → उत्
Replace oṣṭhyapūrvasya with ut. Inherited words (anuvṛtti) may add further conditions.
Commentary
उर् is substituted for the long ॠ of a root when it is preceded by a labial consonant belonging to the root.
As पूर्त and पुपूर्षति from पॄ, so also मुमूर्षति ॥ The lengthening is by 8.2.77. The rule applies when the dento-labial व precedes: as वुवूर्षति ऋत्विजम् from वॄ; so also प्रावुवूर्षति कम्बलम् ॥ The labial consonant must be the consonant of the root. Therefore when ॠ 'to go' is preceded by सम्, the rule will not apply, for म् is not part of the root: as समीर्णम् by 7.1.100.
Vart:- The Guna and Vriddhi do take place in supersession of इर् and उर् substitution. Thus आस्तरणम् and आस्तारकः (from स्तॄ with ल्युट् and ण्वुल्), निपरणम्, निपारकः from पॄ, निगरणम्, निगारकः from गॄ ॥
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.