अपूर्वपदादन्यतरस्यां यड्ढकञौ

Operational rule vidhi

The affixes यत् and ढकञ् come optionally after the word कुल when it is not preceded by any other word which gets the designation of पद -- सुप्तिङन्तं पदम् (1.4.14).

Word by word (padaccheda)

Left context अ- पूर्वपदात् pañcamī · ekavacanaRight context अन्यतरस्याम् saptamī · ekavacanaSubstitute / term य - ढकञौ prathamā · dvivacana

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").
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. Hover or tap one to see its card.

Pink letters are it-markers (anubandhas), tags dropped by 1.3.9. Hover or tap one for the rule that marks it, or try the it-letter finder.

Full reading

अ-पूर्वपदात् अन्यतरस्याम् यत्-ढकञौ

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

Commentary

The affixes यत् and ढकञ् come optionally after the word कुल when it is not preceded by any other word which gets the designation of पद -- सुप्तिङन्तं पदम् 1.4.14.
The word अपूर्वपद means when the word 'kula' is not the last member of a compound. Thus कुल्यः , कौलेयकः ॥ By the use of the word 'optionally,' we get the affix ख also. Thus कुलीनः ॥ The word कु꣡ल्यः has udatta on the first syllable 6.1.213.

The word पद has been defined in (l. 4.14). The word बहु is not a pada. Therefore बहुकुल will take these affixes. Thus बहुकुल्यः , बाहुकुलेयकः and बहुकुलीनः ॥

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