| var. of actino- before a vowel: actinism. |
| 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). |
| actin- pref. Variant of actino-. |
| actino- or actin- pref.
[From Greek aktīs, aktīn-, ray.] |
actino- or actin-
pref.
Actinic radiation: actinotherapy.
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