We've found 6 phrases for blue moon (0.116 seconds):

blue moon »    A long time.

blue moon »    Something absurd.

blue moon »    The moon tinted towards blue as it appears in the sky, caused by dust or smoke in the atmosphere.

blue moon »    The third full moon in a quarter that contains four rather than the usual three full moons.

once in a blue moon »    Never.

once in a blue moon »    Very rarely; very infrequently.

BTW, Why won't you become an editor?