Polyhedral Angle

Geometric figure formed by 2 or more planes that meet at at least one common point called the vertex of the angle. A polyhedral angle is a solid angle.

Examples

This is a dihedral angle :

Dihedral Angle

This figure is formed by two half-planes having a common edge. Line AB is the common edge of the two half-planes.
These are trihedral angles in pyramids :

Angle polyèdre-2

There is a trihedral angle at each vertex of the base of a pyramid. If a pyramid has a triangular base, there is also a trihedral angle at its apex. If a pyramid has a pentagonal base, there is a polyhedral angle at its apex.