Originally Posted by
cyclintom
A "gravel bike" is nothing more than a cyclocross bike. And a cyclocross bike is nothing more than a road bike with enough clearance to fit wider tires.
Although I don't disagree with this, keep in mind that manufacturers are slicing and dicing this segment even more as time goes on. i.e. Cannondale now has the SuperX/CaadX, and the Topstone, the latter being a little more "gravel" than cyclocross.