Line symmetry is when there exists a line (or lines) such that the image of a figure when reflected over the line is itself. A nontrivial rotational symmetry of a figure is a rotation of the plane that maps the figure back to itself such that the rotation is greater than 0° but less than 360°. Reflection symmetry, line symmetry, mirror symmetry, mirror-image symmetry, is symmetry for reflection. That is, a figure which does not change upon undergoing a reflection has reflectional symmetry. Rotational symmetry, also known as radial symmetry in biology, is the property a shape has when it looks the same after some rotation by a partial turn. An object's degree of rotational symmetry is the number of distinct orientations in which it looks the same for each rotation. Remember that symmetry is the word given to define when the same shape appears across a line or point. Line symmetry is perhaps the easier to understand, as it involves a mirror image. Rotational symmetry refers to that kind of symmetry that is rotated around a point.