/ Dictionary / Index R RDX: Meaning and Definition of Find definitions for: RDX Pronunciation: [key] a white, crystalline, water-insoluble, powerful high explosive, CHNO, used chiefly in bombs and shells. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. RDT&E re Related Content Daily Word Quiz: belligerent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language