8.2.40
झषस्तथोर्धोऽधः
Operational rule vidhi
The तकार and थकार that follows a झष् letter is converted to धकार. But this conversion does not happen for the verb root 'धा'.
Word by word (padaccheda)
Left context pañcamī · ekavacanaTarget तथोः ṣaṣṭhī · dvivacanaSubstitute / term धः prathamā · ekavacanaLeft context अधः pañcamī · ekavacana
- Left context Pañcamī (5th case): "after X", the operation applies to what follows (1.1.67 तस्मादित्युत्तरस्य). Also used for limits and sources.
- Target Ṣaṣṭhī (6th case): names what gets replaced, "in place of X" (1.1.49 षष्ठी स्थानेयोगा).
- 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
तथोः धः अधः
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
तथोः → धः / अधः
Replace tathoḥ with dhaḥ when it comes after jhaṣaḥ adhaḥ. Inherited words (anuvṛtti) may add further conditions.
Commentary
ध is substituted for त or थ coming after झष् (झ, भ, घ, ढ, ध) but not after the root धा (दध).
Thus from लभ् we have लब्धा, लब्धुम्, लब्धव्यम्, अलब्ध, अलब्धाः ॥
The भ् of लभ् is changed to ब by 8.4.53. From द्य्ह् — दोग्धा, दोग्धुम्, दोग्धव्यम्, अदुग्ध, अदुग्धाः ॥ The ह is changed to घ by 8.2.32, and then it is changed to ग by 8.4.53.
From लिह :- लेढा, लेढुम्, लेढव्यम्, अलीढ, अलीढाः ॥ In लेढ्धृ &c, the ह्, is changed to ढ by 8.2.31, and ध changed to ढ by 8.4.41, before which the preceding ढ is elided by 8.3.13.
From बुध् :- बोद्धा, बोद्धुम्, बोद्धव्यम्, अबुद्ध, अबुद्धाः ॥ For the ध of बुध् there is substituted द by 8.4.53.
Why do we say "but not after the root धा"? Observe धत्तः धत्थः ॥
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.