A rhombohedron or parallelepiped.
Each flat face of a 3d object is called a face or a polygon!
To determine your face shape look up the general guidelines for each different face shape that there is. Then look in the mirror and compare your face shape.
They both have a face, not a :) face but a side of a shape is called a face and a 2d and 3d shape both show a face of the shape
square
All faces on a cube are equal to each other the shape is of the face on a cube is a square
Each surface of a polyhedron is called a face.
a face.
Octahedron
a triangle
Rectangular !!!
round
In gemology it seems to be called a hexoctahedron. This is a specific shape in which it is as if each face of a cube has a square based pyramid attached, covering its square face. There are others and from Greek it could be called an eicosakaitesserahedron. At least that's how the shapes are usually named!