Even though these 2 English idioms have completely different meanings, they do have something in common: they both use the word blue and If you are curious as i am, i’m pretty sure you’ve wondered many times about where these phrases come from.
Well, wonder no more. We opened up our beloved Oxford Dictionary of English Idioms and we have the answer for you.
Here’s the origin of each idiom. (the article continues after the ad)
Out of the blue
Out of the blue is used when something happens unexpectedly or without warning. But from where does it originate? Well, the phrase refers to a blue, clear sky from which nothing unusual is expected (such as a thunderstorm).
Once in a blue moon
This idiom is used when we refer to something that happens very rarely; practically never. The color blue was an arbitrary choice in this phrase. To say that the moon is blue is recorded in the 16th century as a way of indicating that something could simply, not be true (as the moon will never be blue).
However, a different explanation is given by The American Heritage® New Dictionary of Cultural Literacy dictionary which states that the phrase refers to the second a phenomenon that
If you like what you read, then you will definitely love this one: The Interesting Story Behind The Famous Julius Caesar’s “The Die Is Cast”
Main Article Photo: I’m A Useless Info Junkie, NASA / MSFC
Photoshop: I’m A Useless Info Junkie
Sources: Oxford Dictionary of English Idioms | The New Dictionary of Cultural Literacy: What Every American Needs to Know