/ Dictionary / Index R reverse osmosis: Meaning and Definition of Find definitions for: reverse' osmo'sis Pronunciation: [key] — Chem. Chem. the process in which pure water is produced by forcing waste or saline water through a semipermeable membrane. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. reverse mutation reverse plate Related Content Daily Word Quiz: perspicacious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language