/ Dictionary / Index R radioactive dating: Meaning and Definition of Find definitions for: ra'dioac'tive dat'ing. Pronunciation: [key] See Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. radioactive radioactive decay Related Content Daily Word Quiz: modify Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language