/ Dictionary / Index R RD&D;: Meaning and Definition of Find definitions for: RD&D Pronunciation: [key] research, development, and demonstration. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. RdAc RD&E 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