1) Pertaining to actinism 2) Property 3) Type of ray 
• (a.) Of or pertaining to actinism; as, actinic rays.
1. applied to a radiation : exhibiting actinism 2. applied to other concepts or to devices : referring to actinism
Relating to the chemically active rays of the electromagnetic spectrum. ... Origin: G. Aktis (aktin-), a ray ... (05 Mar 2000) ... 
(ak-tin´ik) producing chemical action; see actinic rays.
Ac·tin'ic adjective Of or pertaining to actinism; as, actinic rays. 
The characteristic of radiation that indicates its capability to produce chemical change. In our industry the term is usually used with reference to UV radiation and its effects on biological systems. Actinic strips are used in UV processing to monitor the intensity of sources. The color or optical density of the strip changes with the exposure.
Type: Term Pronunciation: ak-tin′ik Definitions: 1. Relating to the chemically active rays of the electromagnetic spectrum.
Actinic: Referring to the ultraviolet (UV) rays from sunlight and UV lamps. Sunburn is an actinic burn. An actinic keratosis is a skin lesion that is the consequence of chronic sun exposure. From the Greek 'aktis' meaning 'ray.'Common Misspellings: aktinic
[adj] - relating to or exhibiting actinism
Pertaining to 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. See also: Actinic Ray.
adjective relating to or exhibiting actinism
Relating to the electromagnetic spectrum.
The injurious effects of ultraviolet light.
pertaining to actinism.