/ Dictionary / Index R RDD: Meaning and Definition of Find definitions for: RDD Pronunciation: [key] — Marketing. random digit dialing. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. RDB RDF 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