Definition:Geometric Figure/Three-Dimensional Figure

Definition

A three-dimensional figure is a geometric figure which cannot be embedded in the plane, but which can be embedded in three-dimensional space.

Face of Three-Dimensional Figure

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

Also known as

A common term for a three-dimensional figure is solid figure but this is misleading, as it is usual to be studying the surfaces of such figures, which themselves are not solid as such.

In the words of Euclid:

A solid is that which has length, breadth, and depth.

(The Elements: Book $\text{XI}$: Definition $1$)