PLYWOOD
Veneer plywood (the correct term for what is usually called plywood) is defined as plywood in which all the plies are made of veneers orientated with their plane parallel to the surface of the panel. The term plywood also includes core plywoods such as blockboard and laminboard, which is a ‘wood based panel product consisting of an assembly of plies bonded together, some or all of which are wood’.
The direction of the grain in adjacent plies is normally at right angles, with the outer and inner plies placed symmetrically on each side of a central ply or core.This may be described as cross-banded plywood construction. However, as long as veneer plywood is ‘balanced’ about its centre line, plies may consist of two adjacent veneers bonded with their grain parallel.
The structural properties of plywoods (particularly bending) are related to the direction of the grain of the face veneer. Most plywood is produced with the face grain parallel with 
the long edge of the board and is known as long grain plywood. However, some plywood, notably birch, is largely produced with the face grain at right angles to the long edge of the board; known as cross grain plywood.
