Knowing is half the battle.
Board Foot
A board foot is a unit of measurement for the volume of lumber in the Unites States and Canada. It equals the volume of a board that is one foot (30.5 cm) in length, one foot (30.5 cm) in width, and one inch (2.54 cm) in thickness, or 2.36 liters of wood volume.
Burl
A burl is an abnormal wood growth that creates highly figured wood.
Cookie
A cookie is a large cross section piece of a tree trunk or branch, creating a thick round-ish portion of wood resembling a cookie. Using the term cookie makes it simple to differentiate verbally from a slab of wood that is cut the long way along the tree.
Figured Wood
Figured wood is a general term for unusual patterns in wood grain that can create dramatically beautiful results in woodworking. Figuring has several names that are more descriptive to the visual representation created. Some examples are Quilted, Birdseye, Flame, and Burl.
Janka Hardness
The Janka hardness test, created by Austrian-born American researcher Gabriel Janka, measures the force required to embed an 11.28-millimeter-diameter (7⁄16 in) steel ball halfway into a sample of wood. For standardizing results, hardness testing should be done using 12% moisture content face grain heartwood that is free of knots.
In the United States, the measurement is in pounds-force (lbf). In Sweden, it is in kilograms-force (kgf), and in Australia, either in newtons (N) or kilonewtons (kN). To add more confusion, some people have taken to creating a unit scale specifically for hardness, for example “800 Janka”.
Spalted
Spalting is the coloring of wood by fungal growth in the wood. Zone lines are winding lines and thin streaks of red, brown, and black, and are the most visually dramatic indicator of spalted wood. Spalted woods are sought be woodworkers and furniture makers for their unique organic look.
Spruce – Pine – Fir (SPF)
Spruce-Pine-Fir is a common label for commodity traded dimensional lumber (timber) in North America. These tree species share similar characteristics to the point where lumber derived from any of these species are interchangeable for construction purposes. Further breakdown of this category is done by region and quality, Eastern SPF (generally higher price), Western SPF, Composite SPF (mixed), and utility-grade SPF