/ Dictionary / Index F Frederick William III: Meaning and Definition of Find definitions for: Frederick William III Pronunciation: [key] 1770–1840, king of Prussia 1797–1840. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Frederick William II Frederick William IV Related Content Daily Word Quiz: crutiny Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language