5.3.48 पूरणाद्भागे तीयादन्

Word by word (padaccheda)

Left context पूरणात् pañcamī · ekavacanaRight context भागे saptamī · ekavacanaLeft context तीयात् pañcamī · ekavacanaSubstitute / term अन् prathamā · ekavacana

Left context Pañcamī (5th case): "after X", the operation applies to what follows (1.1.67 तस्मादित्युत्तरस्य). Also used for limits and sources.
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").
Substitute / term Prathamā (1st case): in operational rules, the substitute or the thing introduced; in definitions, the term or its referent.

Dotted words are technical terms. Hover or tap one to see its card.

Full reading

पूरणात् भागे तीयात् अन्

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

Commentary

After a प्रातिपदिक (Nominal Stem) an ordinal number ending in तीय , comes the affix अन् (the word retaining its denotation) when a 'part' is meant.
This sutra is made only to teach accent, for the word to which अन् is added undergoes no other change of form except in accent. Thus द्विती꣡यः 5.2.54 has udatta on ती 3.1.3 but when अन् is added, the accent falls on द्वि 6.1.197. Thus द्वितीयो भागः = द्वि꣡तीयः 'the moiety'. Similarly तृ꣡तीयः 'the one-third'. Why do we say when 'part' is meant? Otherwise, there is no change in accent. The affix तीय always comes in forming ordinal numbers and for no other purpose, for the तीय in words like मुखतीय is not significant as it is not an affix. The employment of the word पूरण in the aphorism is useless for the purposes of this sutra. Its anuvritti, however, runs in the other sutras, and that is the only purpose that it serves here.

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