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
There are also two types of blue moons: monthly and seasonal.
—Joyce Orlando, The Tennessean, 8 Aug. 2024
The last seasonal blue moon was in August 2021, and the next one won't occur until May 2027.
—Tiffany Acosta, The Arizona Republic, 16 Aug. 2024
The second definition − which arose from a misunderstanding of the original − is the monthly blue moon, referring to the second full moon in a single calendar month.
—Marley Malenfant, Austin American-Statesman, 16 Aug. 2024
As with supermoons, there are varying definitions for blue moons — monthly and seasonal.
—Riane Lumer, CNN, 19 Aug. 2024
See all Example Sentences for blue moon 
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Joyce Orlando, The Tennessean, 8 Aug. 2024
The last seasonal blue moon was in August 2021, and the next one won't occur until May 2027.
—Tiffany Acosta, The Arizona Republic, 16 Aug. 2024
The second definition − which arose from a misunderstanding of the original − is the monthly blue moon, referring to the second full moon in a single calendar month.
—Marley Malenfant, Austin American-Statesman, 16 Aug. 2024
As with supermoons, there are varying definitions for blue moons — monthly and seasonal.
—Riane Lumer, CNN, 19 Aug. 2024
See all Example Sentences for blue moon
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 30 Dec. 2024.
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