/ Dictionary / Index B blue moon: Meaning and Definition of Find definitions for: blue' moon' Pronunciation: [key] moon (def. 9). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. blue Monday Blue Mountains Related Content Daily Word Quiz: eccentric Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language