Plywood is a kind of thin plate with three or more layers, which is made by cutting logs into single boards or planing into thin boards and then gluing them with adhesive. Usually made of odd-numbered veneers, the fiber direction of adjacent veneers is vertically arranged and glued. So there are odd-numbered plywood with three, five and seven layers.

Structurally speaking, the outermost veneer of plywood is called panel, and the front panel is called panel, which is the best quality veneer. The opposite surface plate is called back plate, and the second quality veneer is used. The veneer in the inner layer is called core board or middle board, which is composed of the veneer with the worst quality.