ह्रस्वाच्चन्द्रोत्तरपदे मन्त्रे

Operational rule vidhi

In a मन्त्र , the सुट् is added to चन्द्र when it is second member in a compound and is preceded by a short vowel.

Word by word (padaccheda)

Left context pañcamī · ekavacanaRight context चन्द्र- उत्तरपदे saptamī · ekavacanaRight context मन्त्रे saptamī · 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").

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

Full reading

चन्द्र-उत्तरपदे मन्त्रे

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

Commentary

In a मन्त्र , the सुट् is added to चन्द्र when it is second member in a compound and is preceded by a short vowel.
Thus सुश्चन्द्रो युष्मान् ॥ Why do we say after a short vowel? Observe सूर्याचन्द्रमसाविव ॥ Why do we say 'in a Mantra'? Observe, सुचन्द्रा पौर्णमासी ॥ The उत्तरपद can only be in a compound (samasa) as it is well-known to all and it does not mean, 'the second word', as the literal meaning might convey : Therefore the rule does not apply here शुक्रमसि चन्द्रमसि ॥

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