A piste is a marked ski run or path down a mountain for snow skiing, snowboarding, or other mountain sports. This European term is French ("trail", "track") and synonymous with trail, slope, or groomed run in North America.
Individual trails on pistes are graded by difficulty using ski trail ratings.
Piste maintenance 
Pistes are usually maintained using tracked vehicles known as snowcats to compact or groom the snow to even out trail conditions, remove moguls, and redistribute snow to extend the ski season. Natural snow is often augmented with snow making machines early in the season or when the snowpack is low.