Any face on a prism that is not a base is a lateral face (see the attached image). The prism in the picture has a hexagonal base (6 sided) and 6 lateral faces. The lateral faces meet each other at lateral edges, as well as meeting both bases. Each lateral face is a polygon with four sides. All edges of the laterals are the same size and parallel. This makes the lateral faces parallelograms, containing a 4-sided figure with opposite sides that are parallel.