blue moon
noun
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 moon—
Saturday Rev.
Saturday Rev.2
: a second full moon in a calendar month
Synonyms
Examples of blue moon in a Sentence
once in a blue moon we'll get dressed up and eat in a fancy restaurant
Recent Examples on the Web
About 25% of all full moons are supermoons, while only 3% of full moons are considered blue moons.
—John Tufts, The Indianapolis Star, 13 Sep. 2024
The next seasonal blue moon is expected in May 2027.
—Rebecca Schneid, TIME, 18 Aug. 2024
So when will the next super blue moon actually occur?
—Doyle Rice, USA TODAY, 17 Aug. 2024
Similar to supermoons, blue moons happen every two to three years.
—Kelsie Gibson, Peoplemag, 16 Aug. 2024
See all Example Sentences for blue moon 
John Tufts, The Indianapolis Star, 13 Sep. 2024
The next seasonal blue moon is expected in May 2027.
—Rebecca Schneid, TIME, 18 Aug. 2024
So when will the next super blue moon actually occur?
—Doyle Rice, USA TODAY, 17 Aug. 2024
Similar to supermoons, blue moons happen every two to three years.
—Kelsie Gibson, Peoplemag, 16 Aug. 2024
See all Example Sentences for blue moon
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'blue moon.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Dictionary Entries Near blue moon
Cite this Entry
“Blue moon.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/blue%20moon. Accessed 21 Sep. 2024.
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