This is what we found on Wikipedia regarding the Arenacross:

Motorsport (also called motorsports or powersports) are sporting events, competitions and related activities that primarily involve the use of automobiles, motorcycles, motorboats and powered aircraft. For each of these vehicle types, the more specific terms automobile sport, motorcycle sport, power boating and air sports may be used commonly, or officially by organisers and governing bodies.

Different manifestations of motorsport with their own objectives and specific rules are called disciplines. Examples include circuit racing, rallying and trials. Governing bodies, also called sanctioning bodies, often have general rules for each discipline, but allow supplementary rules to define the character of a particular competition, series or championship. Groups of these are often categorised informally, such as by vehicle type, surface type or propulsion method. Examples of categories within a discipline are formula racing, stock car racing, touring car racing, sports car racing, etc.