A variety of āyuṣya (life-span); that life-span, which does not terminate before the time-limit set by the Karma, that is, it is not subjected to any untimely death.
nāpavartyāyuṣo 'napavartyāyuṣah... na hi teṣāmāyuṣo bāhyanimittavaśādaparvato'sti.
(Tavā 2.52.5)