bearclaw: a pattern visible in some spruces that crosses the grain and looks almost as if a bear clawed the tree; usually increases cross-grain stiffness.

bird’s eye: small circular or elliptical areas resembling bird’s eyes on the tangential surface of the wood, formed by indented fibers.

bookmatched: guitar tops and backs created when a single board is cut into two pieces, opened like a book, and joined to show symmetrical matching of the grain.

chatoyance: a change in light reflection or luster across the surface of the wood, typically described as figure, and by the patterns the light reflection creates.

chevron: an arrowed pattern, or inverted V pattern, typically created by the book matching of a set of wood.

curly: a figure pattern that looks like a curl across the surface of the wood.

deflection: a method for measuring stiffness.

density: the specific weight of a wood per unit volume.

fiddle back: a figure pattern occurring on the quarter-sawn face of wood, similar to the pattern of tiger’s stripes.

figure roll: referring to the light play, or chatoyance, as one looks across the surface of the wood.

figure:any distinctive wood grain pattern.

figured: a variation in grain pattern that is visually seen as a change in reflectance, or other dramatic character on the surface of the wood.

flamed: a type of figure in wood, named for a broad curl that forms a flame pattern.

flat sawn: wood that has been cut in an orientation where the growth rings form an angle less than 45 degrees to the wood surface. Also referred to as tangential cut.

flex test: a test designed to measure the amount of flexibility in a piece of wood.

flexibility: referring to the resistance to, or ease of, bending.

grain direction: the direction of the long axes of the dominant longitudinal cells or fibers in a piece of wood.

grain pattern (narrow, medium, etc): the visible dark and light lines; a record of the contrast between summer and winter growth.

grain runout: the angle by which the grain of a piece of wood varies from its natural growth direction; usually a sign of lower quality, lower strength, and lower stiffness.

hardness: resistance to denting.

medullary ray: pith rays radiating outward in every direction from the heart of the stem to the bark. The medullary ray shows strongest on the vertical-grain face of a board.

moon wood (spruce): a name for spruce that was harvested and handled according to Old-World traditions from the Alps region of Europe. The tradition is based on harvesting at specific times dictated by the lunar calendar.

natural resonant frequency: the note at which any material vibrates when struck, bowed or otherwise excited to emit sound.

quarter sawn: wood that has been cut in an orientation where the growth rings form a 90-degree angle (or nearly 90 degrees) to the wood surface. Also referred to as vertical grain or radial cut.

quilted: woods that have a figure similar to puckered cloth; occurs most frequently in maple, and sometimes in mahogany and other woods.

rescued: see salvaged.

ribbon grain: mahogany or other hardwood with parallel bands of alternating grain runout.

rift sawn: wood that has been cut in an orientation where the growth rings form an angle of 45 degrees to the wood surface.

salvaged: when a log is rescued, either from being processed into an inferior product, or from the forest floor, where it might otherwise degrade.

sausage quilt: a type of figure that contains shapes similar to long, tubular bubbles.

sinker: a log that was salvaged from the bottom of a water source; typically the wood leeches minerals from the water, producing a beautiful variegation of color with dramatic contrast.

stiffness: refers to a wood’s resistance to flexing.

sustainable: a system that maintains its own viability by using techniques that allow for continual reuse; conserving an ecological balance by avoiding depletion of natural resources.