A sub-type of Nāma (body-making) Karma, on account of the Udaya (rise) of which there is the emission of cool radiation from the body of a Jīva (living being).
yadudayājjantuśarīrāṇyanuṣṇaprakāśakarūpamudyotaṃ kurvanti yathā yatidevottaravaikriyacandranakṣatratāravimānaratnausadhayastadudyotanāma.
(Prajñā 23.38 Vṛ Pa 474)