actinic keratosis n.
A warty lesion, often premalignant, occurring on the sun-exposed skin of the face or hands, especially of light-skinned persons. Also called senile keratosis.
- Actinic granuloma
actinic granuloma actinic granuloma n. An annular eruption on sun-exposed skin that microscopically shows phagocytosis of dermal elastic fibers by giant cells and histiocytes.
- Actinic ray
a ray of light of short wavelengths, as ultraviolet or violet, that produces photochemical effects. Historical Examples Elusive, delicate, alluring—it is the actinic ray that imparts vitality. Little Journeys to the Homes of the Great, Vol. 1 of 14 Elbert Hubbard The question is, then, what teaching concern in America supplies the best quality of […]
any element of the . noun a member of the actinide series Also called actinon actinide ac·ti·nide (āk’tə-nī’d) n. Any of a series of chemically similar radioactive elements with atomic numbers ranging from 89 (actinium) through 103 (lawrencium). actinide (āk’tə-nīd’) Any of a series of chemically similar metallic elements with atomic numbers ranging from 89 […]
- Actinide series
the series of radioactive elements that starts with actinium and ends with lawrencium. noun a series of 15 radioactive elements with increasing atomic numbers from actinium to lawrencium