THE CAT'S PAJAMAS III

Tad Tuleja 

A collection of the (mostly) true origins of familiar phrases

ONCE IN A BLUE MOON

A blue moon may be the second full moon in a calendar month, or a literally blue moon - due to smoke or dust particles in the atmosphere. But the origins of this expression as meaning "very rarely" or "not very often", go back to 17th century Netherlands in the heyday of northern European capitalist expansion. Dutch commercial interests lay in southeast Asia, so sailors had to endure long absences on voyages that could last for months or even years. One unusually large trade ship was called the Blauwe Maan (Blue Moon), whose appearances in its home port of Amsterdam were so rare they became a byword for infrequency.