Glossary
Actual Size: The true exact measurement of a board or timber in its finished size.
Air Dried: Refers to lumber dried by exposure to air without artificial heat or use of a kiln
Bark Pocket: An opening between annual growth rings that contains bark.
Board Foot: A unit of measure represented by a board 1 inch thick by 12 inches wide by 12 inches long. Board Foot = Thickness (inches) x Width (inches) x Length (feet) / 12.
Bow: The distortion of lumber in which there is a deviation, in a direction perpendicular to the flat face, from a straight line from end to end of the piece.
Check: A lengthwise separation of the wood that usually extends across the rings of annual growth and commonly results from stress set up in wood during drying.
Crown: A convex condition where the center of a board is higher than the edges, opposite of cup. Also, a grade, Crown being the highest or best.
Crook: The distortion of lumber in which there is a deviation, in a direction perpendicular to the end-to-end of the piece.
Cup: A concave condition when the center of a board is lower than the edges.
Distressed: Term used by TWC to describe an appearance grade of antique reclaimed lumber. Describes flooring or lumber specially processed to retain darker color, character marks, nail holes, insect tracks and some of its texture, thereby preserving its natural beauty and evidence of its former use.
Earlywood: The portion of the growth that is formed during the early part of the growing season. It is usually less dense and weaker mechanically than latewood.
End Matched: The ends of each plank are milled with a tongue on one end and a groove on the opposite end, allowing the ends of adjoining planks to interlock when installed.
Equal Lineal Footage: When a multiple width floor is supplied in equal lineal measure, allowing the floor to be installed in a simple repeating pattern.
Equilibrium Moisture Content: The moisture content at which wood neither gains nor loses moisture when surrounded by air at a given relative humidity and temperature.
Flat Grain: Lumber that has been sawn parallel to the pith and approximately tangent to the growth rings. Lumber is considered flat grained when the annual growth rings make an angle of less than 45 degrees with the surface of the piece.
Filler: In woodworking, any substance used to fill the holes and irregularities in planed or sanded surfaces.
Frass: Debris or excrement produced by insects, often found remaining in antique wood.
Growth Ring: The layer of wood growth put on a tree during a single growing season.
Hardness: A property of wood that enables it to resist indentation.
Hardwoods: Generally one of the botanical groups of trees that have broad leaves in contrast to the confers or softwoods. The term has no reference to the actual hardness of the wood.
Heartwood: The wood extending from the pith to the sapwood, the cells of which no longer participate in the life processes of the tree. Heartwood may contain phenolic compounds, gums, resins, and other materials that usually make it darker and more decay resistant than sapwood.
Hygroscopic: Describes a substance that absorbs water or releases water. Wood is hygroscopic and shrinks or swells with changes in moisture content.
Joist: One of a series of parallel beams used to support floor and ceiling loads and supported in turn by larger beams, girders, or bearing walls.
Kiln: A chamber having controlled air-flow, temperature, and relative humidity, for drying lumber and other wood products.
Kiln Dried: Dried in a kiln with the use of artificial heat. Conditions wood to proper moisture content and kills insect and larvae.
Laminate: A process of making a product by bonding together two or more pieces together.
Latewood: The portion of the annual growth ring that is formed after the earlywood formation has ceased. It is usually denser and stronger mechanically than earlywood.
Mastic: A material with adhesive properties which remains pliable with age.
Mineral Streak: An olive to greenish-black or brown discoloration of undermined cause in hardwoods.
Moisture Content: The amount of moisture in wood expressed as a percentage of the weight of oven dried wood.
Nominal Size: As applied to timber or lumber, the size by which it is known and sold in the market; often differs from the actual size.
Old Growth: Timber in or from a mature, naturally established forest. Virtually all trees that are large enough to produce wide planks are by nature “Old Growth”. This term is often used in a confusing and misleading manner to describe wide plank wood flooring, implying that the lumber is either Antique or Virgin rather than what it is, lumber from large commercially harvested trees.
Plainsawn: Another term for flat-grained lumber.
Pith: The small, soft core occurring near the center of a tree trunk, branch, or log.
Pre-finished: In wood flooring, describes a product with the finish applied at the factory thereby needing only to be installed.
Rays: In wood, strips of cells extending radially within a tree and varying in height from a few cells in some species to 4 or more inches in oak. The rays serve primarily to store food and transport it horizontally in the tree. In quartersawn oak, the rays form a conspicuous figure, sometimes referred to as flecks.
Relative Humidity: Ratio of the amount of water vapor present in the air to that which the air would hold at saturation at the same temperature.
Remilled: Term used by TWC to describe an appearance grade of antique reclaimed lumber. Describes flooring or lumber milled from timbers and dimension stock to produce a refined floor with a lot of character and a lighter more uniform appearance than a “Distressed” appearance.
Resin: Inflammable, water-soluble, vegetable substances secreted by certain plants or trees, and characterizing the wood of many coniferous species, The term is also applied to synthetic organic products related to the natural resins.
Sapwood: The wood of pale color near the outside of the log. Under most conditions the sapwood is more susceptible to decay than heartwood.
Saw Kerf : Grooves or notches made in cutting with a saw. The portion of a log, timber or other piece of wood removed by the saw in parting the material into two pieces.
Shake: A separation along the grain, the greater part of which occurs between the rings of annual growth. Usually considered to have occurred in the standing tree or during felling.
Softwoods: Generally, one of the botanical groups of trees that in most cases have needlelike or scalelike leaves; the conifers, also the wood produced by such trees. The term has no reference to the actual hardness of the wood.
Square Footage: A unit of measure to determine area, typically calculated by multiplying the length times width.
Twist: A distortion caused by the turning or winding of the edges of a board so that the four corners of any face are no longer in the same plane
Vapor Barrier: A material with a high resistance to vapor movement, such as foil, plastic film, or specially coated paper, that is used in combination with insulation to control migration of moisture or condensation.
Vertical Grain: Lumber that has been sawn so that the wide surfaces extend approximately at right angles to the annual growth rings. Lumber is considered edge grained when the rings form an angle of 45 degrees to 90 degrees with the wide surface of the piece.
Wane: Bark or lack of wood from any cause on edge or corner of a beam or plank.
Warp: Any variation from a true or plane surface. Warp includes bow, crook, cup, and twist, or any combination thereof.