Idiom of the Day:

Once in a blue moon

If something happens

“once in a blue moon,” it means that it is a rare event. Maybe there is a friend of yours that you only get to see “once in a blue moon” because of scheduling conflicts or due to long distance. The origin of this idiom comes from the moon changing colors due to recent natural disasters. Typhoons, fires, volcanic eruptions, etc. can kick up a lot of dust in the atmosphere, making the moon appear blue.