Terminology

Term	Definition
Plywood	Wood-based panel consisting of an assembly of layers glued together with the direction of the grain in adjacent layers usually at right angles.
Balanced plywood	Plywood in which the layers are symmetrical about the central layer with respect to thickness, grain orientations and species.
Veneer plywood	Plywood in which all the layers are made of veneers oriented parallel to the plane of the panel.
Core plywood	Plywood having a core.
Blockboard	Core plywood, the core of which is made of strips of solid wood more than 7 mm wide but not wider than 30 mm, which may or may not be glued together.
Laminboard	Core plywood, the core of which is made of strips of rotary cut veneer, not thicker than 7 mm, placed on edge, all or most of which are glued together.
Composite plywood	Plywood, the core (or certain layers) of which is made of materials other then solid wood or veneers. There are at least two crossbanded layers on each side of the core.
Moulded plywood	Plywood which is not flat, made by pressing in a mould.
Long grain plywood	Plywood in which the grain of the outermost plies is parallel or nearly parallel to the long edge of the panel.
Cross grained plywood	Plywood in which the grain of the outermost plies is parallel or nearly parallel to the short edge of the panel.
Layer	Either one ply or two or more plies glued together with their grain direction parallel or another material.
Cross band	Inner layer with grain direction at right angles to the outermost plies.
Core	Central layer visible on the edges of the manufactured panel, generally thicker than the other layers and consisting of: - blocks or strips of wood placed side by side which are or are not be glued together; - other wood-based material; - other sheet material; - cellular construction.
Veneer	Thin sheet of wood not more than 7 mm in thickness.
Sliced veneer	Veneer produced by slicing.
Rotary cut veneer	Veneer produced by peeling.
Ply	Either one single veneer or two or more veneers joined edge to edge or end to end.
Surface	Visible part of outermost ply of a plywood.
Face	The better quality surface of a plywood.
Back	The opposite surface to the face.
Length of a panel	The panel dimension in the direction of the grain of the outermost layers.
Width of a panel	The panel dimension at right angle to the length.
Thickness of a panel	Dimension perpendicular to the surface of the panel.
Grain	General direction or arrangement of fibres.
Angle grain	Grain forming an oblique angle with the edges of a ply.
Spiral grain	Grain that follows a spiral course around the pith.
Interlocked grain	A characteristic of a wood where the fibres in succeeding growth periods incline alternately in opposite directions.
Veining	Network formed by veins of wood on the surface of veneer.
Curly grain	Grain that follows thight irregular curves.
Knot	Portion of a branch embedded in the wood.
Intergrown knot	Knot which is intergrown for at least 3 of its perimeter with the surrounding veneer.
Partially intergrown knot	Knot which is intergrown for 1 to 3 of its perimeter with the surrounding veneer.
Non adhering knot	Knot which is intergrown for less then 1 of its perimeter with the surrounding veneer.
Knot hole	Void produced by the removal of a knot.
Sound knot	Knot showing no indication of rot.
Pin knot	Sound intergrown knot of no more than 5 mm diameter.
Check	Separation of the fibres which does not extend through the thickness of the veneer.
Splint	Separation of the fibres which extend through the thickness of the veneer.
Stain	Any variation from the natural colour of wood, which is not associated with a loss of strength.
Resin pocket	Lens-shaped cavity in timber containing or that has contained resin.
Bark pocket	Bark that is partly or wholly enclosed in the wood.
Roughness	Unevenness of the surface due to irregularities of the structure of the wood or due to defective manufacturing.
Open joint	Discontinuity between two adjacent elements in a ply.
Overlap (joint)	Defect due to overlapping of two adjacent veneers (or two sections of a split veneer) in a ply.
Blister	Localised separation caused by area of glue bond failure between plies.
Bump	Local area of over-thickness showing in an outermost ply.
Hollow	Local depression in an outermost ply.
Imprint	Local indentation caused by foreign matter being pressed into a surface.
Inclusion	Foreign matter embedded in a veneer.
Plywood sanded only on one side	Plywood the face or back of which has been smoothed by means of a mechanical sander.
Plywood sanded on both sides	Plywood the face and back of which has been smoothed by means of a mechanical sander.
Scraped plywood	Plywood the face and/or back of which has been smoothed by means of a mechanical scraper.
Overlaid plywood	Plywood surfaced with one or several overlay sheets or one or several films such as: - impregnated paper; - plastic; - resin film; - metal; - decorative veneer.
Textured plywood	Plywood modified by mechanical method to create greater surface relief.
Veneered plywood	Plywood which is overlaid by a decorative wood veneer.
Sanding through	Local absence of the outer ply resulting from excessive sanding which reveals some of the glue line (and/or the underlying ply).
Glue penetration	Glue which has seeped through the outer ply and which can show up as blemishes.
Inserting	Repairing of a ply by an element of determinated shaped sound veneer, inserted to replace defective portions which have been previously removed.
Patch (or plug)	Piece of determined shaped veneer for inserting.
Shim	Piece of long and narrow shaped veneer for inserting.
Filling	Repairing by sealing of open defects with filler.
Bond	Adhesion by means of glue.
Lay-up	Arrangement of layers in a plywood.
Composition	Description of constituent elements of plywood.
Cup	Curvature of a panel across the width.
Bow	Curvature of a panel across the length.
Twist	Spiral distorsion of a panel

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