Plywood is made of three or more thin layers of wood veneer bonded together with an adhesive. Each layer of wood veneer is usually oriented with its grain running at right angles to the adjacent layer in order to reduce the shrinkage and improve the strength of the finished piece.
There are two outer layers of plywood known respectively as the face and the back. The face is the good side, while the back remains unused or hidden unless the plywood has two good faces. The center layer is known as the core. In plywood with five or more plies, the intermediate layers are known as the cross bands.
Plywood may be made from hardwoods, softwoods, or a combination of the two.