What is the point group of square?

The point group of a square is (D_{4h}). This group includes the symmetries of the square, which consist of rotations (90°, 180°, and 270°) and reflections (through the diagonals and the midpoints of the sides), as well as an inversion center. The presence of both rotational and reflectional symmetries characterizes it as a dihedral group with horizontal mirror symmetry.