Pāṇini sūtras

kā and kavaṅ are optionally the substitutes of ku when uṣṇa follows.

1. kavamकवम्

   Part	Lexeme	Sandhi form	Meaning	Stem
   kक्	kavamकवम्	kavamकवम्	kavam [word]	kavamकवम्

2. ca+uṣṇeच+उष्णे

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   cच्	caच	caच	besides	caच
   uउ	uṣṇaउष्ण	uṣṇeउष्णे	uṣṇa [word]उष्ण [wओर्द्]	uṣṇउष्ण् + plus eए

Anuvṛtti

1. uttara+padeउत्तर+पदे 6·3·1

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   uउ	uttaraउत्तर	uttaraउत्तर	last	uttarउत्तर् + plus aअ
   pप्	padaपद	padeपदे	word	padपद् + plus eए

2. koḥकोः 6·3·101

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   kक्	kuकु	koḥकोः	ku [word]	kक् + plus oḥओः

3. kāका 6·3·104

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   kक्	kāका	kāका	kā-का-	kक् + plus āआ

4. vibhāṣāविभाषा 6·3·106

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   vव्	vibhāṣविभाष्	vibhāṣāविभाषा	option	vibhāṣविभाष् + plus āआ