Life-span-determining Karma-
A type of Karma the Udaya (rise) of which is responsible for a definite Bhavasthiti of the Jīva (soul), i.e., life-span in a particular life-form, and due to the Udaya of which a Jīva (soul) lives in a particular life-form like infernal etc., (for the period of time decided by it) and due to the cessation of which, the Jīva is called dead.
eti bhavasthitiṃ jīvo yena iti āyuḥ.
(Jaisidī 4.3 Vṛ)
ā samantādeti-gacchati bhavād bhavāntarasankrāntau vipākodayamityāyuḥ.
(Prajñā Vṛ Pa 454)
yasyodayāt prāyogyaprakṛtiviśeṣānuśāyībhūta ātmā nārakādibhāvena jīvati yasya ca kṣayānmṛta ucyate tadāyuḥ.
(TaBhā 8.11 Vṛ)