radiance vs visible radiation

radiance and visible radiation both are nouns.

Word	Noun	Adjective	Verb	Adverb
radiance	Yes	No	No	No
visible radiation	Yes	No	No	No

As nouns, visible radiation is a hypernym of radiance; that is, visible radiation is a word with a broader meaning than radiance:

radiance: the amount of electromagnetic radiation leaving or arriving at a point on a surface
visible radiation: (physics) electromagnetic radiation that can produce a visual sensation

Other hypernyms of radiance include light, visible light.

radiance (noun)	visible radiation (noun)
the quality of being bright and sending out rays of light	(physics) electromagnetic radiation that can produce a visual sensation
the amount of electromagnetic radiation leaving or arriving at a point on a surface
an attractive combination of good health and happiness