<P> Owing to the rarity of a blue moon , the term `` blue moon '' is used colloquially to mean a rare event , as in the phrase `` once in a blue moon '' . </P>
<P> Owing to the rarity of a blue moon , the term `` blue moon '' is used colloquially to mean a rare event , as in the phrase `` once in a blue moon '' . </P>
where does the phrase once in a blue moon originate
where does the phrase once in a blue moon originate
Owing to the rarity of a blue moon
Owing to the rarity of a blue moon