What makes a console "next-gen"...?

[watsuke]

Mazty said:

watsuke said:
Actually, since the Wii U is out, it's a current gen system. Next gen is only used to refer to a generation that hasn't begun yet. It's incredibly simple to understand...

But then that makes every game that hasn't been released next-gen, which we all know isn't the case. 

What? If the games are being made for the PS4 or NextBox, yeah they are next-gen games. If they are being made for the current gen consoles (i.e. PS3, XBOX 360, Wii U), they are current gen games.