This
database is a comprehensive collection of all the American idioms and slang available.
American Idioms are many and varied. We hope you enjoy our collection. We are adding more all the time.
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The Post Office regularly fails to deliver checks sent in payment to me, but bills sent to me fail to be delivered only once in a blue moon. Two full moons in the same month are extremely rare, though they do happen. A second full moon has come to be called a blue moon. This is apparently because the Maine Farmers Almanac used to list the date of first moon in red text, and the second moon in blue.