Plywood is a sheet material manufactured from thin veneers (or plies) of wood which have been bonded together using an adhesive. There are usually an odd number of veneers to each sheet or panel and each veneer has its grain direction at right angles to its two adjacent veneers.
Historically, evidence has been found of laminated wood products in the tombs of the Egyptian Pharaohs and it is known that the Chinese shaved wood and glued it together a thousand years ago. But it was not until the early 1930s that plywood manufacture took off in the USA.
The choice of timber species, the type of adhesive used and the quality and thickness of the veneers dictate the end-use applications to which the material can be put. Today, plywood can be either a structural product or a non-structural material. By structural we mean that it can take an engineering load and can be used as a building element to support a structure. By non-structural we are referring to decorative sheets which take no engineering load.
Today, plywood is manufactured all around the world from both hardwood and softwood trees. It is traded internationally and is used for construction, packaging, transportation, and decorative items, to name just a few uses.
A more recent derivative of plywood manufacture has been the development of LVL or laminated veneer lumber.