Working with plywood, as with many other things in life, means dealing with some special vocabulary. If you’re new to woodworking or even new to working with plywood, you may not know these terms. Without them, you won’t necessarily know what you’re dealing with.
Back – plywood side with the lower face grade, normally used as the back when installed
Core – inner layers of the plywood, with grain running perpendicular to the face
Cross Grain – a manufacturing defect where a piece of face veneer runs perpendicular to the board’s length
Cross Lamination – the orientation of successive veneer layers, placing them perpendicular to the adjacent layers of the plywood
Cut – refers to how the veneer is made; either rotary cut or sliced
Delamination – failure of plywood panels, where the adhesive used to attach the plies fails, usually due to water
Face – the side of the plywood with the higher grade finish
Grade / Grading – the system by which the quality of plywood’s surfaces is identified
Grain – the growth pattern of wood fibers
Gum Spot – sap or resin left over on wood veneer from milling
Hardwood – any wood that comes from a deciduous tree (one whose leaves fall off) – has nothing to do with the wood’s density
Heartwood – the center of the log, below the sapwood; also the strongest part of the log
Knot – a place on a log where a branch grew out
Knot Hole – a knot that has separated from the wood around it, leaving a hole
Pin Knot – a small knot, less than ¼” in diameter
Tight Knot – a knot that has not separated from the wood surrounding it
Open Knot – a hole or void in lumber where a knot has come out
Lap – the place where two pieces of veneer are laid next to each other in the same ply
Marine Plywood – high quality plywood made with waterproof glue and without any voids
LVL (Laminated Veneer Lumber) – an engineered plywood product made of highly compressed, pressure-cooked wood fibers combined with synthetic resin
Mineral Streak – discoloration of hardwood
Weathering – browning, graying or yellowing caused by exposure to the elements
Particleboard – an engineered wood product manufactured from small wood particles (sawdust) with a bonding resin – not the same as MDF, which is a higher grade product
Patch – material placed on defects in face veneers to repair voids, etc.
Ply – a single layer of wood veneer in a plywood product
Plywood – originally referred to an engineered wood product made by laminating several plies of wood veneer perpendicular to each other. The definition has now been expanded to include all engineered wood sheet products
Rotary Cut – the process by which veneer is peeled off a log as one continuous sheet on a lathe
Sapwood – the outer layers of living wood, just below the bark; normally not used in plywood
Checks – cracks in the wood veneer, running parallel to the wood grain
Veneer – a sliced or peeled layer of thin wood, used to make plywood
