rădĭātĭo — Lewis & Short
rădĭātĭo, ōnis, f.id.,
I a glittering, shining, a beamy lustre, radiation (postAug.):
marmoris,Plin. 36, 5, 4, § 32: stellarum, Jul. Firm. Math. 1, 4. — Plur., Arn. 6, 208.