Pāṇini sūtras

Anaṅ (an) is substituted for the final of the stems ending in ṛ, as well as for the final of uśanas, purudanśas, and anehas, in the Nominative Singular (but not in the Vocative Singular).

1. ṛ+t+uśanaḥ+purudaṃsaḥ+anehasāmऋ+त्+उशनः+पुरुदंसः+अनेहसाम्

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   ṛऋ	ṛऋ	ṛऋ	ṛkāraऋकार	ṛऋ
   tत्	tत्	tत्	TT	tत्
   uउ	uśanasउशनस्	uśanaḥउशनः	uśanas [word]उशनस् [wओर्द्]	uśanउशन् + plus aḥअः
   pप्	purudaṃsasपुरुदंसस्	purudaṃsaḥपुरुदंसः	purudaṃsas [word]पुरुदंसस् [wओर्द्]	purudaṃsपुरुदंस् + plus aḥअः
   aअ	anehasअनेहस्	anehasāmअनेहसाम्	anehas [word]	anehअनेह् + plus asāmअसाम्

2. caच

   Part	Lexeme	Sandhi form	Meaning	Stem
   cच्	caच	caच	besides	caच

Anuvṛtti

1. a+sambuddhauअ+सम्बुद्धौ 7·1·92

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   aअ	aअ	aअ	not	aअ
   sस्	sambuddhiसम्बुद्धि	sambuddhauसम्बुद्धौ	vocative	sambuddhसम्बुद्ध् + plus auऔ

2. sauसौ 7·1·93

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   sस्	suसु	sauसौ	suसु	sस् + plus auऔ