नदीपौर्णमास्याग्रहायणीभ्यः

Operational rule vidhi

The affix टच् comes optionally after an अव्ययीभाव समास ending in 1. नदी 2. पौर्णमासी and 3. आग्रहायणि.

Word by word (padaccheda)

Left context - पौर्णमासी- आग्रहायणीभ्यः pañcamī · bahuvacana

Left context Pañcamī (5th case): "after X", the operation applies to what follows (1.1.67 तस्मादित्युत्तरस्य). Also used for limits and sources.

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

Full reading

-पौर्णमासी-आग्रहायणीभ्यः

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

Commentary

The affix टच् comes optionally after an अव्ययीभाव समास ending in 1. नदी 2. पौर्णमासी and 3. आग्रहायणि।
Thus नद्याः समीपम् = उपनदम् or उपनदि, उपपौर्णमासम् or उपपौर्णमासि, उपाग्रहायणम् or उपाग्रहायणि ॥

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