Definitions

1. adjective

relating to or affecting the skin, especially in relation to the effects of the sun or other forms of radiant energy

“Actinical damage to the skin can be severe and lead to premature aging.”

2. noun

a substance, such as a chemical or a dye, that is sensitive to radiant energy, such as light

“Actinicals are commonly used in scientific experiments to study the effects of light on various materials.”