In snowboarding and skiing, carving is a turning technique that can most elegantly be defined as a turn where every point along the board's edge passes over the same point in the snow. An alternative definition is a turn where the direction of travel is always the same as the direction the board is pointing.
Carving is achieved through putting the board on its edge, pressuring that edge, and allowing the sidecut of the board to make it turn. There is virtually no turning, steering, or "kicking" the board required by the carver.
A carved turn leaves a clean knife-edge line in the snow, unlike the far more common skid-turn, where the board skids sideways throughout the turn, leaving a broader track.
A purely carved turn will begin on the downhill edge - it is often possible to see the base of a good carver's board from a position higher up the hill.
Carved turns result in far less loss of speed than skid-turns, which is why they are favoured by racers. Speed control when carving is achieved by travelling across the fall line, and sometimes even uphill for a short distance. Expert carvers are even capable of crossing their own track, ie, performing a 360.
Many people claim to be able to carve turns. Some people use "carving" as a generic term for "turning". Only a select few skiers and snowboarders, however, can actually carve a turn.