Cross-country cycling is defined by the terrain on which it is performed. Cross-country courses and trails consist of a mix of rough forest paths, single or double tracks, smooth fire roads, and even paved paths connecting trails together. Cross-country trails are deemed "easy" or "intermediate" and rely more on physical prowess than technical ability.
Trail riding mountain bikes are typically ridden on mountain trails, fire roads, logging roads, and other unpaved trails. These types of terrain commonly include rocks, washouts, ruts, loose sand, loose gravel, roots, and steep slopes or ski runs, sometimes accessed using ski lifts.
Trail riding above 3000m
Enduro in its most basic definition is a type of mountain bike race where the downhills are timed, and the uphills are mandatory but not timed. Riders are timed in stages that are primarily downhill, with neutral "transfer" stages in between. The transfer stages usually must be completed within a time-limit, but are not part of the accumulated time.
Downhill mountain biking (DH) is a genre of mountain biking practiced on steep, rough terrain that often features jumps, drops, rock gardens and other obstacles.
Freeride is a discipline of mountain biking closely related to downhill mountain biking, dirt jumping and freestyle BMX. The focus is on tricks, style, and technical trail features.