Plywood is a wood product manufactured out of many sheets of veneer, or plies, pressed together and glued, with their grains going in opposite directions. Plywood tends to be extremely strong and is treated in many different ways depending upon its intended application. Because of the way in which plywood is constructed, it also resists cracking, bending, warping, and shrinkage, depending upon its thickness. Plywood is also referred to as an engineered wood, although it is made from a composite of wooden materials, and various forms of it have been made for thousands of years.

The plies that form plywood are generally cut on a rotary lathe, which cuts a continuous roll of wood while a log, called a peeler, is turned against it. Rotary lathing is rapid and makes efficient use of the wood while turning out veneers highly suitable for plywood.

Rotary lathe veneers tend to be dull in appearance, although perfectly functional for use as a countertop core. After the veneers are cut, they are overlaid with layers of glue and pressed together until dry to form a flat, even, tight piece of plywood. Plywood is sturdier than regular sheets or panels of wood, because the veneers are laid with their grains opposing, which also causes the wood product to resist warping because the grains pull each other tight.

Plywood comes in a number of forms, including softwood plywood, which is made from pine, fir, or spruce. Softwood plywood is usually pale in color and is used in construction applications. Plywood can also be decorative, with a facing veneer of exotic hardwoods. Mahogany or birch is used to create an extremely strong type of plywood known as aircraft plywood, because it was utilized in the construction of aircraft through the Second World War.

When plywood is destined for use as a countertop core in an indoor application, it is made with urea-formaldehyde glue, which dries quickly and is a good value. For plywood intended for use in outdoor applications or wet environments, a more expensive water resistant glue is used to prevent the plies from coming apart, or delaminating, and compromising the strength of the plywood. Plies range in thickness depending upon the plywood panels they are used in, from 1/10 inch (approximately 1/5 centimeter) to 1/6 inch (almost 1/5 centimeters). Standard plywood sizes consist of four foot by eight foot (1.2 by 2.4 meter) sheets in three, five, or seven plies. Plywood intended for countertop applications is normally manufactured in a ¾" thickness (23/32") features 7 ply construction and comes in 30" by 8’, 10’ and 12’ lengths. Plywood cores for countertop construction are sometimes a specification requirement for HUD installations.