Cyclo-cross bikes are predominantly designed to be used in Cyclo-cross races, although some of the entry level cyclo-cross bikes are designed to be used as a more multi use cycle, with the inclusion of mudguard eyes, bottle cage bosses and carrier eyes included, so whilst the frame is suited to cyclo-cross use, it could also be used for light touring, Audax or as a winter / training bike.
From the cyclo-cross point of view, mud clogging is the major issue that the cyclo-cross frame has to overcome, consequently cantilever brakes are used, larger clearances for the tyres at the seat stays, chain stays and forks, bottle cage bosses are not generally fitted as cyclo-cross races are relatively short and bottles would probably be knocked out of the cages due to vibration. The cables are generally routed over the top of the top tube, again to prevent mud clogging.
Cinelli Cyclo-Cross frames
Colnago Cyclo-Cross Bikes & frames
Pinarello Cyclo-Cross bikes & frames.