radiance

UK: /ˈreɪdiəns/ US: /ˈreɪdiəns/ ,(rā′dē əns)

WordReference Random House Learner's Dictionary of American English © 2025

ra•di•ance /ˈreɪdiəns/   n. [uncountable]

1. radiant brightness or light:
   the radiance of the dawn.
2. warm, cheerful brightness:
   a smile full of radiance.

WordReference Random House Unabridged Dictionary of American English © 2025

ra•di•ance  (rā′dē əns), n. 

1. radiant brightness or light:
   the radiance of the tropical sun.
2. warm, cheerful brightness:
   the radiance of her expression.
3. Slang Terms [Rare.] radiation.

Also, radiancy. 

• radi(ant) + -ance 1595–1605

Synonyms

• 1. . resplendence, splendor, brilliance.

Collins Concise English Dictionary © HarperCollins Publishers::

radiance / ˈreɪdɪəns/, radiancy noun ( -ances, -ancies)

1. the quality or state of being radiant
2. a measure of the amount of electromagnetic radiation leaving or arriving at a point on a surface. It is the radiant intensity in a given direction of a small element of surface area divided by the orthogonal projection of this area onto a plane at right angles to the direction