Also found in: Thesaurus, Acronyms, Idioms, Encyclopedia, Wikipedia.
a. The third full moon in a three-month calendrical season that has four full moons.
b. The second of two full moons occurring in the same month.
2. Informal A relatively long period of time: I haven't seen you in a blue moon.
[Sense 2, probably from the rare occurrence whereby the moon appears blue from high amounts of dust in the atmosphere, as from a volcanic eruption.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
1. the second full moon occurring within a calendar month
2. once in a blue moon informal very rarely; almost never
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
Switch to new thesaurus
|Noun||1.||blue moon - a long time; "something that happens once in blue moon almost never happens"|
colloquialism - a colloquial expression; characteristic of spoken or written communication that seeks to imitate informal speech
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
The American Heritage® Roget's Thesaurus. Copyright © 2013, 2014 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.