6.4.151
आपत्यस्य च तद्धितेऽनाति
Operational rule vidhi
The य् of a Patronymic affix, preceded by a consonant, is elided before a तद्धित when it does not begin with an आ.
Word by word (padaccheda)
Target आपत्यस्य ṣaṣṭhī · ekavacanaIndeclinable च avyayaRight context saptamī · ekavacanaRight context अनाति saptamī · ekavacana
- Target Ṣaṣṭhī (6th case): names what gets replaced, "in place of X" (1.1.49 षष्ठी स्थानेयोगा).
- Indeclinable An avyaya such as च "and", वा "optionally", न "not".
- 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, dashed ones pratyāhāras (names for classes of sounds or affixes). Hover or tap one to see its card.
Full reading
आपत्यस्य च अनाति
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
Commentary
The य् of a Patronymic affix, preceded by a consonant, is elided before a तद्धित when it does not begin with an आ।
Thus गर्गाणां समूहः = गार्गकम् from गार्ग्य, वात्सकम् from वात्स्य 4.2.37 — 4.2.40. Why do we say 'a Patronymic य'? Observe सांकाश्यकः, काम्पिल्यकः 4.2.80.
The repetition of the word Taddhita indicates that the elision takes place some-times of the non-patronymic य also, as सामी इष्टिः ॥
Why do we say 'not beginning with a long आ'? Observe गार्ग्यायणः, वात्स्यायनः ॥ The य should be preceded by a consonant, otherwise we have कारिकेयस्यापत्यं = कारिकेयिः ॥ Why do we say 'when followed by a Taddhita affix'? Observe गार्ग्ययोः, वात्स्ययोः (before the Genitive and Locative dual affixes).
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.