8.3.3
आतोऽटि नित्यम्
Operational rule vidhi
In this रूत्वप्रकरण, The रुँ that gets constructed at end of a पद causes an अनुनासिक of the आकार just preceding it.
Word by word (padaccheda)
Target आतः ṣaṣṭhī · ekavacanaRight context saptamī · ekavacanaSubstitute / term नित्यम् prathamā · ekavacana
- Target Ṣaṣṭhī (6th case): names what gets replaced, "in place of X" (1.1.49 षष्ठी स्थानेयोगा).
- 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, dashed ones pratyāhāras (names for classes of sounds or affixes). Hover or tap one to see its card.
Full reading
आतः नित्यम्
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
आतः → नित्यम् /
Replace ātaḥ with nityam when aṭi follows. Inherited words (anuvṛtti) may add further conditions.
Commentary
A nasal vowel is ALWAYS substituted for आ before रु when it is followed by a letter of अट् प्रत्यहार (i.e. when it is followed by a vowel or ह , य , व or र).
Thus 8.3.9 teaches रु substitution of म, the long आ preceding it, would have been optionally nasal by the last sutra. The present sutra makes it necessarily so. Thus महाँ असि (Rig. III.46.2) महाँ इन्द्रो य ओजसा (Rig. VIII.6. I). देवाँ अच्छादीव्यत् ॥
Some (i. e. the Taittariyas) read it as anusvara. This is a Vedic diversity.
Why do we say "for a long आ"? Observe ये वा वनस्पतीरनु ॥ Why do we say "when a vowel or ह, य, व, or र follows"? Observe भवांश्चरति, भवांश्छादयति ॥
The word नित्य 'always' is employed for the sake of distinctness only. The very fact of making a separate sutra, would give it a compulsory force, even without the word nitya.
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.