8.4.25
अयनं च
Operational rule vidhi
The नकार of अयन is converted to णकार when this word follows the word 'अन्तर्'. But this णत्व does not happen if the resultant word indicates the name of a place.
Word by word (padaccheda)
Substitute / term अयनम् prathamā · ekavacanaIndeclinable च avyaya
- Substitute / term Prathamā (1st case): in operational rules, the substitute or the thing introduced; in definitions, the term or its referent.
- Indeclinable An avyaya such as च "and", वा "optionally", न "not".
Full reading
अयनम् च
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
Commentary
The न of अयन is changed to ण , when preceded by the word अन्तर् and the word does not denote a country.
Thus अन्तरयणं शोभनम् ॥ Why do we say "not denoting a country"? Observe अन्तरयनो देशः ॥ This ण change would have taken place by 8.4.29, this special sutra is for आदेश purposes. The word अयन is formed by ल्युट् added to अय् or इण् ॥
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.