/ Dictionary / Index U USNG: Meaning and Definition of Find definitions for: USNG Pronunciation: [key] United States National Guard. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. usnea usnic acid Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language