/ Dictionary / Index A actinotherapy: Meaning and Definition of Find definitions for: ac•tin•o•ther•a•py Pronunciation: (ak-tin"ō-ther'u-pē, ak"tu-nō-), [key] — n. Med. radiotherapy, esp. using ultraviolet rays. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: actinotherapy (Thesaurus) actinopterygian actinouranium Related Content Daily Word Quiz: menagerie Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language