- an unlimited period. “Once in a blue moon.”
More About blue moonPosition in the dictionary: 253 of 4022 slang words.
Next words in the dictionary: blue murders., blue ruin, blue-pigeon-flyer, blued, blues, bluey, bluff, blunt, blurt out, board-of-green-cloth
Previous words in the dictionary: blue devils, blue butter, blue bottle, blue blanket, blue billy, blue bellies, blue, bludger, blowsey, blower