actino-

a combining form with the meaning “ray, beam,” used in the formation of compound words, with the particular senses “radiation” in the physical sciences (actinometer) and “having raylike structures,” “radiate in form” in biology (actinomyces; actinopod).

Also, especially before a vowel, actin-.

Origin

< Greek, combining form representing aktī́s (genitive aktînos) ray, beam; see -o-

British Dictionary definitions for actino-

actino-

combining form

indicating a radial structure: actinomorphic

indicating radioactivity or radiation: actinometer

Word Origin

from Greek aktino-, from aktis beam, ray

Word Origin and History for actino-

before vowels actin-, word-forming element meaning "pertaining to rays," from Greek aktis (genitive aktinos) "ray, radiance;" perhaps cognate with Sanskrit aktuh "light, ray," Gothic uhtwo "dawn, daybreak," Lithuanian anksti "early."

actino- in Medicine

actino- or actin-
pref.
Actinic radiation: actinotherapy.