/ Dictionary / Index R radiolucent: Meaning and Definition of Find definitions for: ra•di•o•lu•cent Pronunciation: (rā"dē-ō-l'sunt), [key] — adj. almost entirely transparent to radiation; almost entirely invisible in x-ray photographs and under fluoroscopy. Cf. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: radiolucent (Thesaurus) radiology radioluminescence Related Content Daily Word Quiz: portent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language