/ Dictionary / Index G Gustavus IV: Meaning and Definition of Find definitions for: Gustavus IV Pronunciation: [key] (Gustavus Adolphus) 1778–1837, king of Sweden 1792–1809 (son of Gustavus III). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Gustavus III Gustavus V Related Content Daily Word Quiz: procrastinate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language