Glossary of Terms
A glossary of industry terms:
• Backs: The reverse side to the face of a plywood panel. Generally, the poorer side of any grade plywood panel calling for a face and a back.
• Bark Pocket: A small area of bark around which normal wood has grown.
• Burl: A swirl or twist in the grain of wood, usually occurring near a knot, but which itself does not contain a knot.
• Core: The innermost portion of plywood usually composed of veneer. Also referred to as a “center.” A core may also be made of fiberboard, particleboard or lumber.
• Crossbar: An imperfection or irregularity in the grain of wood running at right angles to the length of the board.
• Cross banding: Inner ply veneer placed at right angles to the core, face and back of a plywood panel.
• Defects: Anything interrupting the smooth flow of a wood surface. This includes loose knots, splits, voids, wormholes, bark pockets and others.
• Delamination: The separation of the inner plies in a panel due to the failure of the adhesive bond.
• Face: The best side of a plywood panel in which the outer veneers are of different grades.
• Grain: The pattern, size and direction of the fibers in wood or veneer.
• Gum Spots: Accumulation of resinous material often found on panel surfaces. May be removed by sanding.
• Half-Round Slicing: Off-center slicing cut slightly across the annular grown rings resulting in half-round, plain sliced or rotary characteristics.
• Hardwood: General term referring to the wood of many different deciduous trees as opposed to the softwood of evergreen or coniferous trees. Does not relate to the density of the wood.
• Knot: Circular portion of a board or veneer that was once the base of a branch or twig growing from the trunk of a tree.
• Knot (Open): Opening produced when a portion of a know has dropped out or separated due to seasoning.
• Knot (Pin): Sound knots less than 1/4″ in diameter.
• Knot (Sound): Knots that are solidly fixed by growth and retain their place in lumber or veneer.
• Knothole: Opening produced when knots drop from the wood in which they were once embedded.
• Lap: The overlapping of one piece of veneer on another in the same layer of ply.
• Medium Density Fiberboard (MDF): A panel or core material manufactured from pressure-cooked wood fiber, resin and wax.
• Mineral Streak: A discoloration of hardwood and hardwood veneer.
• Particleboard: A panel or core material manufactured from pressed sawmill shavings, resin and wax.
• Patches: Filler material inserted into defects of veneers or panels for repair.
• Plain Sliced: Veneer sliced from a log tangent to the tree’s annual rings.
• Ply: A single sheet of veneer forming one layer in a multi-layered piece of plywood.
• Plywood, Hardwood: A panel composed of layers of inner plies, or other core material joined with an adhesive to a face veneer of hardwood and a back veneer, usually also composed of hardwood.
• Quarter Slicing: Quartered log sliced at right angles to the growth rings.
• Rift Cut: Veneer cut from a quartered log on a 90-degree angle to the grain.
• Rotary Cut: Veneer peeled from a whole log set in a lathe and turned against a special knife
• Sapwood: The light colored, living portion of a tree located between the heartwood and the bark.
• Slip Matched: Veneer sheets that are laid side by side to form a whole sheet with a repetitive grain appearance.
• Splits: Separations of the wood fiber running parallel to the grain.
• Veneer: Peeled or sliced thin sheets of wood used as inner plies or as decorative faces.