Blue moon tonight: What does that mean, anyway?

[koalabear]

Tonight's moon is what's now called a "seasonal blue moon." It's the third full moon in a season that has four, rather than the usual three, according to Space.com. That's actually the original definition of the term, which is thought to come from an Old English word meaning betrayer, because a third full moon usually means the end of a season. Seasonal full moons are rare. Miss this one, and you won't get another chance until May 21, 2016.

http://local.msn.com/blue-moon-tonight-what-does-that-mean-anyway

 

[Asshungry]

Tonight's moon is what's now called a "seasonal blue moon." It's the third full moon in a season that has four, rather than the usual three, according to Space.com. That's actually the original definition of the term, which is thought to come from an Old English word meaning betrayer, because a third full moon usually means the end of a season. Seasonal full moons are rare. Miss this one, and you won't get another chance until May 21, 2016.

http://local.msn.com/blue-moon-tonight-what-does-that-mean-anyway

Ive always heard a blue moon represents the second full moon in any given month. Either way they dont happen very often, hence the saying " once in a blue moon "

 

[warrior queen]

It's a moon.
Seriously, unless you're an astronomer or one of those moon-worshipping tribal people, the most that folks are gonna do is look up and say "Oooh, pretty!"