6.4.132
वाह ऊठ्
Operational rule vidhi
भसंज्ञक वाह् is converted to 'ऊठ्' by सम्प्रसारणम्.
Word by word (padaccheda)
Target वाहः ṣaṣṭhī · ekavacanaSubstitute / term ऊठ् prathamā · ekavacana
- 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. Hover or tap one to see its card.
Full reading
वाहः ऊठ्
Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.
वाहः → ऊठ्
Replace vāhaḥ with ūṭh. Inherited words (anuvṛtti) may add further conditions.
Commentary
The व is vocalised to ऊ (ऊठ्) when the compound अङ्ग (stem) is भ।
The word वाह् is a ण्वि formed stem by 3.2.64. It can never stand alone, but, must be preceded by an upapada: hence we have used the word "compound." Thus प्रष्ठौहः, प्रष्ठौहा, प्रष्ठौहे, दित्यौहः, दित्यौहा, दित्यौहे ॥ By 6.1.108, ऊ + आ (of वा) = ऊ; and then प्रष्ठ + उह् = प्रष्ठौहः; the Vriddhi being substituted by 6.1.89. This form could have been evolved by simple samprasarana thus : प्रष्ठ + वह् + शस् = प्रष्ठ + उह् + अस् 6.1.108 = प्रष्ठ + ओह् + अस् (the affix ण्वि 3.2.64, will produce guna) = प्रष्ठौहः 6.1.88. In fact ण्वि is never added to वह् 3.2.64 unless the preceding member ends in अ and that अ + ओ of वा will always produce औ ॥ The making of this special samprasarana in ऊठ्, indicates the existence of following maxim: असिद्धं बहिरङ्गमन्तरङ्गे; and the samprasarana being a bahiranga operation, is considered as asiddha for the purposes of guna which is an antaranga operation : therefore, we can never get the form ओह ॥
Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.