actino-
a. Gr. ἀκτῑνο- combining form of ἀκτίς (gen. ἀκτῖν-ος) a ray, a beam, as in ἀκτῑνοβόλος darting rays. Entering into numerous derivatives, chiefly connected (1) with actinism, (2) with animals related to the Actinia. actinodermatitis, dermatitis arising from the action of actinic rays; actinomorphic a. = actinomorphous a.
| 1906 Dorland Med. Dict. (ed. 4) 27/1 Actinodermatitis..X-ray dermatitis. |
| 1898 H. C. Porter tr. Strasburger's Textbk. Bot. i. i. 16 Such parts of plants as may be divided by each of three or more longitudinal planes into like halves are termed either..Radial, or Actinomorphic. |