blue moon

noun

Definition of blue moon

  1. 1 :  a very long period of time —usually used in the phrase once in a blue moon such people happen along only once in a blue moonSaturday Rev.

  2. 2 :  a second full moon in a calendar month

Examples of blue moon in a Sentence

  1. once in a blue moon we'll get dressed up and eat in a fancy restaurant

1821

First Known Use of blue moon

1821



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