Cross-country skiing (commonly abbreviated XC skiing) is a winter sport in which participants propel themselves across snow-covered terrain using skis and poles. It is popular in many places with large snowfields, primarily Northern Europe, Canada, and Alaska.
Cross-country skiing is part of the Nordic skiing sport family, which also includes ski jumping, and a combination sport of cross-country skiing and ski jumping called Nordic combined. Free-technique cross-country skiing is also the method of locomotion in the combination sport of Biathlon, which adds rifle marksmanship to skiing. Another combination sport is ski-orienteering, which adds the skill of map navigation along snow trails and tracks.
Reference: Wikipedia Cross-country Skiing