actinic ray

noun

, Physics.

1. a ray of light of short wavelengths, as ultraviolet or violet, that produces photochemical effects.

Word History and Origins

Origin of actinic ray¹

First recorded in 1835–45

Example Sentences

The three kinds were partially separated by a prism, the actinic rays being generally more refracted, and the thermal rays less refracted than the luminous.

From Project Gutenberg

Of or pertaining to actinism; as, actinic rays.

From Project Gutenberg

It is a very familiar fact that when material bodies are heated they emit electromagnetic radiations, in the form of thermal, luminous, and actinic rays, in appreciable quantities.

From Project Gutenberg

The peculiar property which it possesses, of darkening under the actinic rays of the sun, makes it essential that it be combined with other, more stable pigments to prolong its life when exposed to weather.

From Project Gutenberg

The glasses did not reduce the quantity of light, as do smoked glasses, but the quality; the actinic rays, which do the greatest harm, were eliminated.

From Project Gutenberg