Breadcrumb Home > Dictionary > Index U UI: Meaning and Definition of Find definitions for: UI Pronunciation: [key] unemployment insurance. u.i. Pronunciation: [key] ut infra. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. uhuru* Uigur ✖ Related Content Daily Word Quiz: triumphalism Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language