Breadcrumb Home > 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: hortatory Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language