CX v Road bike - what's the difference?

[Mandog]

Is it just componentry eg a CX bike will have lower gear ratio, canti brakes and tougher rims for wider knobbly tyres?

Or is there a difference in the geometry of the frame as well?

[Mandog]

Well to answer my own question the Boardman CX Pro has a 72' HA and 43.5 cm CS length v a Team Carbon road bike has a 73' HA and 40.5 CS. So I guess the road bike will be easier to manual.