Definition:Geometric Figure/Three-Dimensional Figure/Face

Definition

The faces of a three-dimensional figure are the surfaces which form its extremities.

In the words of Euclid:

An extremity of a solid is a surface.

(The Elements: Book $\text{XI}$: Definition $2$)

Also see

• Results about faces of solid figures can be found here.

Also see

• Definition:Face of Polyhedron: when the three-dimensional figure is a polyhedron, the faces are polygons.