/ Dictionary / Index O onrush: Meaning and Definition of Find definitions for: on•rush Pronunciation: (on'rush", ôn'-), [key] — n. a strong forward rush, flow, etc. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: onrush (Thesaurus) on-record Onsager Related Content Daily Word Quiz: dentifrice Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language