A type of curve is a mathematical concept that describes the shape of a line or surface. The three solutions for the term TYPE OF CURVE are ESS (3 letters), PARABOLA (8 letters), and SINE (4 letters). An ESS is an elliptical curve, which is a smooth, closed curve that forms a loop. A PARABOLA is a curved line that forms a U-shape and is used to describe the path of a projectile. Finally, a SINE is a wave-like curve that is used to describe periodic functions such as sound and light.