/ Dictionary / Index G Guido d'Arezzo: Meaning and Definition of Find definitions for: Gui•do d'A•rez•zo Pronunciation: (gwē'dô dä-ret'tsô), [key] — (Guido Aretinus) (“Fra Guittone”), c995–1049?, Italian monk and music theorist: reformer of musical notation. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. Guido guidon Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language