Property of radiant energy

• The property of radiation that enables it to produce photochemical effects

Wiktionary Word definitions in Wiktionary
n. (context chemistry physics English) That property of electromagnetic radiation that leads to the production of photochemical effects

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Actinism \Ac"tin*ism\, n. [Gr. ?, ? ray.] The property of radiant energy (found chiefly in solar or electric light) by which chemical changes are produced, as in photography.

Wikipedia Word definitions in Wikipedia
Actinism is the property of solar radiation that leads to the production of photochemical and photobiological effects. Actinism is derived from the Greek ακτίς, ακτῖνος (a ray or beam). The word actinism is found, for example, in the terminology of imaging ...

WordNet Word definitions in WordNet
n. the property of radiation that enables it to produce photochemical effects