Natural Edge – refers to items that are turned such that the shape of the exterior of the tree impacts the outward edge of a piece.  The outward edge on hollow forms is around the top opening.  On a bowl, it represents the rim.  This style is also sometimes known as living edge or bark edge, as the contours found on the outside of the tree are used to develop this look.

Hollow Form – a sculptural form of woodwork where the interior material of a form is removed, rendering the object hollow.  This is different from a bowl in that the dimension of the opening is much smaller than the overall diameter of the object itself.  These forms tend to be variations on a spherical object that incorporate multiple curvatures.

Lap Bowl – a bowl style variation that uses a smooth or round bottom.  It may be thought of as not having a base or that the base is a single point.

Utility Bowl – a bowl that is created with a functional aspect in mind.  They have food safe finishes and have a base that is approximately 1/3 the diameter of the rim or larger to add stability to the item.

Ambrosia – a fungal pattern found in trees, most often in maple trees, that has been introduced by the borings of an Ambrosia beetle.  The pattern is generally seen as streaks of oranges, blues, purples, yellows, and browns around the beetle borings.

Nested – describes a series of bowls that fit inside of each other.

Spalting – a randomized wood characteristic created by the presence of mold and fungus in the wood itself.  It is a visual result of the stages of decay in a tree.  Spalting can have a wide variation, since the species of the tree, type of mold/fungus, and local environment all are factors in the outward appearance.

Burl– also called gnarls or other colloquial names, they generally look like growths that resemble warts or tumors on a tree.  Burls are essentially deviations of the normal growth pattern of a tree, usually perpendicular to the normal grain direction, brought about by injury, disease, fungus/mold, insect damage, etc.  They can be found either in the root ball of a tree or growing above the surface.  The species of a tree sometimes has impact on what part of the tree the burls are found, and some species form burls more readily than others.  Burl wood is mostly an uncommon occurrence and is sought after by woodworkers for its dramatic colors and variations.  Its been my experience that burl wood is more stable and usually hollows more easily than other parts of a tree.  I have also noticed in North Carolina that they tend to occur more frequently in environments near water.

Voids – areas in the outside shape of an object that experience material loss and generally look like irregular holes.  They are often formed from rotten areas in a tree, weak inclusions, or turning natural edge pieces where the contours are extreme.

Inclusions – sometimes called bark inclusions, are areas in a tree where the core wood of a tree is not consistent, resulting in a bark layer.  Inclusions are common in burl wood and also typical in crotch sections, or areas where two limbs grow together but have not completely fused.

Nut and Bolt Design – the standard concept of a bolt, washer, and nut.  In this context, the bolt, washer, and nut are all made of wood and the bolt and nut have been turned with threads in the wood.

Coring – a method of retrieving multiple bowls from a singular blank.  Each of the bowls are “scooped” out of the recesses of the next larger bowl.  This method is used to created nested bowls.

Blank – a starting chunk of wood that has yet to be turned.  Wood in this stage has been sawn from the tree itself to form a raw bulk of material.

Rough Bowl – the intermediate stage of turning a bowl from a blank to a bowl that is thicker than its final size.  Bowls at this stage are generally of a thickness that is 1/10 the diameter of the rim.  Bowls are left rough in this stage to finalize drying and let stresses reach equilibrium.

Zone Lines – the black randomized patterned lines left behind by the growth of fungus or mold.  They are commonly found in wood that has been or is spalted.