Definitions for "Rotational symmetry"
A term that describes a shape that remains unchanged when it is turned less than 360 degrees about a fixed point
The rotational symmetry of any figure is determined by counting the number of times it semblance repeats or reproduces itself in one rotation about an axis. Only four kinds of rotational symmetry are possible among regular figure; these are twofold, threefold, fourfold, and sixfold. For example a cube has twofold, threefold and fourfold rotational symmetry.
A figure has -fold rotational symmetry if the figure can be rotated   degrees about a point (where is a positive integer) in such a way that the resulting image coincides with the original figure (Lesson 0.1).