Cyclocross bikes are a type of bike used mainly for cyclocross events. During this events, a rider using a cyclocross bike is expected to quickly dismount, lift the bike as he or she navigates through the obstructions or barriers placed on the way. Road bikes, on the other hand, are a type of bike designed specifically to be used in road cycling competitions, and also for normal leisure biking.
Other names for these types of bikes are racing bikes and roadies. As you would expect, cyclocross bikes are made light weighted frames, whereas the road bike frame weighs more compared to that of a cyclocross bike. Also, the cyclocross bike frame is more durable compared to that of road bikes. This is because cyclocross bikes are designed so that they can easily be controlled by a rider. Another difference is that road bikes are made with tires that are 23 millimeters wide, whereas cyclocross bikes are made with a rim that can fit perfectly for both thin tires and wide tires.