/ Dictionary / Index U USN: Meaning and Definition of Find definitions for: USN Pronunciation: [key] United States Navy. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: usn (Thesaurus) USMS USNA Related Content Daily Word Quiz: acquiesce Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language