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Air-dried timber: Timber dried by exposure to air in a yard or shed, without artificial heat
(also see seasoning).

Arris: The sharp intersection of two surfaces, eg. face and edge of a piece of timber.

Backcut: Cut so that the wide face of the piece is a tangential plane to the growth rings. Trade practice in Australia is to class timber as backcut when the average inclination of the growth rings to the wide face is less than 45 degrees, and to class veneer as backcut when the growth rings are nominally parallel to the face of the veneer.

Boxed Heart: The pith and the adjacent wood contained within the four surfaces of a piece of timber anywhere in its length

Equilibrium moisture content (EMC): The moisture content at which timber neither gains nor loses moisture from the surrounding atmosphere

Fibre saturation point: The point in the seasoning or wetting of timber at which the cell cavities are free from water but cell walls are still saturated with bound water. Itis taken as approximately 25–30% moisture content

Green timber: Unseasoned, wet, with free water present in the cell

Heart: The portion of a log that includes the pith and the associated defective wood

Heartwood: The wood making up the centre part of the tree, beneath the sapwood. Cells of heartwood 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

Insitu: In situation

Lignin: One of the principal chemical constituents of wood cellular tissue – the binding agent

Longitudinal: Generally parallel to the direction of the wood fibres

Lyctid borer: Larva of the family Lyctidae, commonly the species Lyctus brunneus Steph., which attacks starch sapwood of some seasoned or partially seasoned, pored timbers. The adult beetle makes the flight hole. Syn. Powder-post borer

Lyctid susceptibility: Timber is classified according to its susceptibility to attack by lyctid borer. Legislation governs the sale and use of lyctid susceptible timber in NSW and Queensland; Australian Standards limit the use of lyctid susceptible sapwood throughout Australia

Moisture content: The weight of moisture contained in a piece of timber expressed as a percentage of the oven dry weight

Nominal size: The named size, or ordered size, which may vary from the actual size of
the piece because of variations due to sawing, shrinkage and dressing and the tolerances allowed on these operations

Quarter sawn timber: Timber in which the average inclination of the growth rings to the wide face is not less that 45 degrees

Radial: Coincident with a radius from the axis of the tree or log to the circumference

Radially sawn: Timber sawn on the radius from the central axis of the tree or log to the circumference, perpendicular to the growth rings. The resulting pieces are generally triangular in shape

Sapwood: Outer layers of wood which, in a growing tree, contain living cells and reserve materials such as starch. Under most conditions the sapwood is paler in colour and more susceptible to decay than heartwood

Tangential: Coincident with a tangent at the circumference of a tree or log, or parallel to such a tangent. In practice, it often means roughly coincident with a growth ring

Unseasoned timber: Timber in which the average moisture content exceeds 25%