/ Dictionary / Index O Otto IV: Meaning and Definition of Find definitions for: Otto IV Pronunciation: [key] c1175–1218, king of Germany 1208–15; emperor of the Holy Roman Empire 1209–15. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Otto III Otto cycle Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language