(Greek: a suffix; pertaining to; of the nature of, like; in chemistry, it denotes a higher valence of the element than is expressed by -ous)

actinic (adjective) (not comparable)
1. A reference to radiation, such as sunlight or x-rays: A sunburn is an actinic burn while actinic keratosis is a skin lesion that is caused by chronic sun exposure.
2. Regarding photochemical properties: Some actinic attributes are found in containers that protect them from photo-degradation.
3. Pertaining to or designating radiant energy: An actinic ray exists in the visible and ultraviolet spectrum which produces marked chemical changes.
actinic carcinoma (s) (noun), actinic carcinomas; actinic carcinomata (pl)
A basal cell or squamous cell cacinoma of the face and other exposed surfaces of the body: Actinic carcinoma is seen in people who spend prolonged periods of time in direct sunlight.
actinic conjunctivitis (s) (noun), actinic conjunctivitides; actinic conjunctivitises (pl)
An inflammation of the conjunctiva (transparent membrane covering the eyeball): Actinic conjunctivitis can be caused by exposure to the ultraviolet radiation of sunlight or other sources, such as exposure to acetylene torches, therapeutic lamps (sun lamps), and klieg lights (powerful carbon-arc lamps producing intense light and used especially in making movies).

"Actinic" is the adjective referring to ultraviolet (UV) rays from sunlight and UV lamps.

actinic dermatitis (s) (noun), actinic dermatitises; actinic dermatitides (pl)
A skin inflammation or rash resulting from exposure to sunlight, X-rays, or atomic particle radiation: Chronic or recurrent actinic dermatitis can lead to skin cancer.
actinocarpic (adjective), more actinocarpic, most actinocarpic
A reference to plants with flowers radially arranged: Actinocarpic vegetation or plants have the placentas radiate from the center of the axis of the fruit.
actinogenic (adjective). more actinogenic, most actinogenic
Referring to the production of radiation: Actinogenic formation of rays or radiation is especially exemplified by ionising radiation.
actinolitic (adjective), more actinolitic, most actinolitic
Of the nature of, or containing, actinolite which is the bright green variety of amphibole occurring usually in fibrous or columnar masse: "Amphibole" is any of a complex group of actinolitic minerals containing chiefly calcium, magnesium, sodium, iron, and aluminum, and including hornblende, tremolite, asbestos, etc., and occurring as important constituents of many rocks.
actinometric (adjective), more actinometric, most actinometric
1. Pertaining to actinometry: An actinometric measurement can judge the intensity of the solar rays, either by (a) heating or by (b) actinic means.
2. A reference to any of several radiometric instruments: An actinometric device can be a pyrheliometer, which is used chiefly for meteorological measurements of terrestrial and solar radiation.
Capable of being divided into equal halves along any diameter, as the flowers of the rose or tulip; radially symmetrical.
actinomorphic (adjective), more actinomorphic, most actinomorphic
In botany, a reference to radial symmetry: The tulip and the rose are two examples of actinomorphic flowers in that the longitudinal halves are proportional to each other, or balanced with each other.
actinomycotic (adjective) (not comparable)
Relating to actinomycosis: The actinomycotic inflammatory disease can arise in cattle, hogs, and sometimes in humans, is caused by microorganisms of the genus Actinomyces, and characterized by lumpy tumors of the mouth, neck, chest, and abdomen.
actinophonic (adjective) (not comparable)
A reference to the production of sounds that are created by chemical action: Since Joe was interested in the creation of noises, he decided to investigate and learn more about the actinophonic phenomena dealing with ultraviolet rays.
acyclic (adjective), more acyclic, most acyclic
1. In botany, a reference; especially. to flowers whose parts are arranged in spirals rather than in whorls, as with magnolias.

A whorl is an arrangement of leaves, petals, sepals, etc., in a circle around the stem.

2. In chemistry, having an open-chain molecular structure rather than a ring-shaped structure.