The sidecut is the inner curvature of a ski, snowboard, or skiboard. It is measured as the distance between the waist of the board and an imaginary line drawn from the widest points at the tip and tail. It can also be reported as the radius of the curve of the side cut, depending on the type of mathematical function (e.g. parabolic, circular) it follows. Parabolic skis (skis with a pronounced parabolic sidecut) were first introduced by Elan in 1993, and since then have completely taken over the alpine skiing industry. The nature of the sidecut assists in making refined carving turns.