/ Dictionary / Index R radiopaque: Meaning and Definition of Find definitions for: ra•di•o•paque Pronunciation: (rā"dē-ō-pāk'), [key] — adj. opaque to radiation; visible in x-ray photographs and under fluoroscopy (opposed to radiotransparent). Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: radiopaque (Thesaurus) radionuclide radiophare Related Content Daily Word Quiz: transient Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language