## Definition of symmetry

**:**balanced proportions; also

**:**beauty of form arising from balanced proportions

**:**the property of being symmetrical; especially

**:**correspondence in size, shape, and relative position of parts on opposite sides of a dividing line or median plane or about a center or axis — compare bilateral symmetry, radial symmetry

**:**a rigid motion of a geometric figure that determines a one-to-one mapping onto itself

**:**the property of remaining invariant under certain changes (as of orientation in space, of the sign of the electric charge, of parity, or of the direction of time flow) —used of physical phenomena and of equations describing them