/ Dictionary / Index G GU: Meaning and Definition of Find definitions for: GU Pronunciation: [key] genitourinary. Guam (approved esp. for use with zip code). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: gu (Thesaurus) G guacamole Related Content Daily Word Quiz: endear Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language