/ Dictionary / Index R rason: Meaning and Definition of Find definitions for: ra•son Pronunciation: (rä'sôn Eng. ras'on), [key] — pl. ra•sa a long, loose, black gown with wide sleeves, worn by the clergy. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Rasmussen rasophore Related Content Daily Word Quiz: abominable Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language