actino-, actin-, actini-, -actinal, actis- +

(Greek: ray [as of light] or like a ray in form; radiance, radiation; a radiating or tentacled structure)

actinozoan
Saltwater animals, such as corals, sea anemones, sea fans, etc.
actinula
An advanced larva in the life cycle of certain hydrozoans that possesses a mouth and tentacles, and may attach and develop into a new hydroid colony (as in Tubularia or hydroids having large, naked, flowerlike hydranths at the summits of long, slender, usually simple, stems) or metamorphose into a medusa (tentacled, usually bell-shaped, free-swimming jellyfish).
adiactinic
Not capable of transmitting actinic rays or those relating to the chemically active rays of the electromagnetic spectrum.
cervicofacial actinomycosis
A form of actinomycosis (chronic local or systemic granulomatous, a inflammatory lesion, infection caused by a fungus) characterized by slow-growing inflammatory lesions of the lymph nodes that drain the mouth (lumpy jaw), reddening of the overlying skin, and intraperitoneal abscesses.
hexactine
Sponge anatomy including a spicule with six equal and similar rays meeting at right angles.

Spicule is a small pointed structure serving as a skeletal element in various marine and freshwater invertebrates; such as, sponges and corals

stauractine
Ractinal spicule with all four rays in a single plane.

A spicule is a small pointed structure serving as a skeletal element in various marine and freshwater invertebrates; such as, sponges and corals.

tetractine, tetraxon, tetractinal
A spicule (small spike or needle-like body) of four equal and similar rays meeting at equal angles