The crossword solution for the term 'curly shape' is ESS, which stands for the mathematical symbol for an ellipse. An ellipse is a closed curve in a plane, which is defined by two focal points and the sum of the distances from any point on the curve to the two focal points is constant. It is a type of conic section, which is a curve that is created by the intersection of a plane and a cone. Ellipses are often used in physics and engineering, and they can also be used to describe orbits of planets and other celestial bodies.