Backs: Some plywood panels are specified with different grades of veneer on each side. The lower grade side of a plywood panel is called the Back.
Bark Pocket: An area on a sheet of veneer where a tree branch grew, thus trapping a small amount of bark, usually around a knot.
Core: Inner plies of a panel product, usually composed of veneer. Alternatively, cores can be made of particleboard, MDF or lumber.
Crossbar: A defect in panel manufacturing where a piece of veneer runs perpendicular to the length of the board.
Crossbanding: Crossbanding refers to the orientation of successive layers of veneer layup by placing them perpendicular to the face and back of a plywood panel.
Defects: Any number of imperfections in a panel product’s appearance or surface, including splits, stains, voids, holes, open knots, bark pockets and other issues.
Delamination: Panel separation caused by adhesive failure.
Face: Some plywood panels are specified with different grades of veneer on each side. The higher-grade side of a plywood panel is called the Front.
Flitch: The complete bundle of thin sheets of veneer after cutting, laid together in sequence as they were sliced or sawn.
Grain: The distinctive, natural pattern, size and direction of the fibers in sliced or sawn wood.
Gum Spots: Sap or resin left on wood from veneer sawing or slicing. Gum spots can usually be removed by sanding.
Half-Round Slicing: When a log is cut tangential to its growth rings, the result is a plain sliced or rotary grain pattern.
Hardwood: Any species of deciduous tree lumber or veneer. Coniferous tree lumber is called Softwood. The term Hardwood has no relationship to the density of the wood.
Heartwood: The oldest part of a log radiating from the center, consisting of mature wood that has stopped growing. Usually, heartwood is darker than sapwood.
Knot: The place on lumber or veneer where a branch once emerged from the trunk of the tree.
Knot (Open): The condition of a knot that has separated from the fibers surrounding it due to the drying process.
Knot (Pin): Very small knots less than 1/4" in diameter.
Knot (Sound): Knots that have not separated from the surrounding fiber during the drying process.
Knothole: A void in lumber or veneer created when a knot is missing from its original location.
Lap: Orientation of two pieces of veneer next to one another in the same layer of ply.
Medium Density Fiberboard (MDF): A wood flour material made 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: Material placed onto defects in veneers to repair voids and other imperfections.
Plain Sliced: When a log is cut tangential to the tree’s annual growth rings.
Ply: One layer in a wood panel product. Varying numbers of plies make up a sheet of plywood.
Plywood, Hardwood: A panel product with a hardwood face veneer. The back veneer is usually hardwood as well. Hardwood plywood may or may not have softwood inner plies.
Quarter Slicing: A veneer cutting method in which a log is sliced at right angles to the annular growth rings.
Rift Cut: A veneer cutting method in which a log is cut into quarters and then at a 90-degree angle to the grain direction.
Rotary Cut: A peeling process whereby a whole log is set in a lathe and turned against a large knife.
Sapwood: The youngest, newest wood in a lumber or veneer, located between the heartwood and the bark.
Slip Matched: When veneer is carefully aligned to form a whole sheet with a pleasing grain appearance.
Splits: Cracks in the wood fiber running parallel to the grain in veneer, usually from drying.
Veneer: Peeled or sliced sheets of thin wood used to make the layers of plywood.