/ Dictionary / Index R rapidity: Meaning and Definition of Find definitions for: ra•pid•i•ty Pronunciation: (ru-pid'i-tē), [key] — n. a rapid state or quality; quickness; celerity. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: rapidity (Thesaurus) rapid fire rapidly advancing juvenile periodontitis Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language