/ Dictionary / Index U U-boat: Meaning and Definition of Find definitions for: U-boat Pronunciation: (y'bōt"), [key] — n. a German submarine. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: u-boat (Thesaurus) ubi supra* U bolt Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language