/ Dictionary / Index M Magnus Annus*: Meaning and Definition of Find definitions for: Mag•nus An•nus Pronunciation: (mäg'noos än'noos), [key] — Latin. Latin. the Great Year: a cycle of years, usually a thousand, that begins with a Golden Age, steadily deteriorates, and ends with a universal catastrophe, either a fire or a flood. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. magnum opus Magnus effect Related Content Daily Word Quiz: supercilious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language