/ Dictionary / Index R radiotoxic: Meaning and Definition of Find definitions for: ra•di•o•tox•ic Pronunciation: (rā"dē-ō-tok'sik), [key] — adj. Pathol. causing radiation sickness. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. radiothorium radiotracer Related Content Daily Word Quiz: dissonant Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language