सम्बुद्धौ च

Operational rule vidhi

An आबन्त अङ्ग gets an एकारादेश in presence of the सुँ-प्रत्यय of सम्बोधन-एकवचन.

Word by word (padaccheda)

Right context सम्बुद्धौ saptamī · ekavacanaIndeclinable च avyaya

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").
Indeclinable An avyaya such as च "and", वा "optionally", न "not".

Dotted words are technical terms, dashed ones pratyāhāras (names for classes of sounds or affixes). Hover or tap one to see its card.

सम्बुद्धौ च

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

ए is substituted for the final आ of the feminine affix, in the Vocative Case singular.
As हे खट्वे, हे बहुराजे, हे कारीषगन्ध्ये ॥

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