It is a regular quadrilateral which is a square
A plane
No. A square is a plane figure and conventionally for plane figures symmetry is considered in terms of rotation about a point or an axis (in the plane of the figure) but not a plane outside the plane of the square.
a face.
It is a figure that is the same as another figure in the plane. A square is the same plane figure as another square, but a cube is same the same plane figure even tho it is made up of 6 squares.
octahedron
pentahedron
If you ask this, you fail Octahedron
yes, a square can only exist on a plane in euclidean geometry.
A hexahedron is a solid with six plane faces, and a cuboid is a six-sided figure each face of which is a rectangle.
rectangle
A Dodecahedron has twelve pentagonal faces. A Dodecagon is a plane figure with twelve sides.
They are five plane shapes!