Pertaining to shortwave electromagnetic radiation capable of initiating photochemical reactions, as in photography or the fading of pigments. Because of the particularly strong action of ultra-violet radiation on photochemical processes, the term has come to be almost synonymous with ultraviolet, as in actinic rays.
a. dermatitis — that produced by exposure to actinic radiation, such as that from the sun, ultraviolet waves, or x- or gamma radiation. Called also dermatitis actinica.
a. radiation — said of rays of light beyond the violet end of the spectrum.