Pāṇini sūtras

The words denoting time, being in the accusative case, are optionally compounded with a word ending in the affix kta, and the resulting compound is Tat-purusha.

1. kālāḥकालाः

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   kक्	kālaकाल	kālāḥकालाः	time	kālकाल् + plus āMआM

Anuvṛtti

1. dvitīyāद्वितीया 2·1·24

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   dद्	dvitīyaद्वितीय	dvitīyāद्वितीया	second	dvitīyद्वितीय् + plus āआ

2. ktenaक्तेन 2·1·25

   Part	Lexeme	Sandhi form	Meaning	Stem + termination
   kक्	ktaक्त	ktenaक्तेन	ktaक्त	ktक्त् + plus enaएन