Wood Terms - A Lumber Glossary from A - Z

A complete "Woodipedia" of lumber terms for experts & amateur woodworkers alike.

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Woodipedia Index A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Wood Terms that Start with "J"
Lumber Glossary Term Definition

Joists and Planks


A device used for suspending a loading-line lead block from a skyline.


An unskilled example or display of logging work. Contemptuous expression applied to an unskilled piece of work in logging, particularly in felling, where several trees are lodged and/or crisscrossed.


A lightweight, two-drum yarder usually on a truck with a spar and boom; may be used for both short distance yarding and loading. Frame mounted on a sled or vehicle for loading logs.

Jammer Logging Cable logging system generally restricted to one skidding line and used for winching logs up to 300 feet from the cutting area to a log collection point.
Janka Test

A hardness test, usually for wood flooring, the rating is pounds of pressure required to press a steel ball .444 inches in diameter one half way into the wood.


A device used to make special cuts, guide a tool, or aid in woodworking operations.

Jig Saw

A power tool that cuts by moving a blade up and down as it is guided through the cut.


A machine to true the edges of boards usually in preparation for gluing.

  • Adhesive Joint – The location at which two adherents are held together with a layer of adhesive.
  • Assembly Joint – Joints between variously shapes parts or subassemblies such as in wood furniture.
  • Butt Joint – An end joint formed by abutting the squared ends of two pieces.
  • Edge Joint – A joint made by nodding two pieces of wood together edge to edge, commonly by gluing. The joints may be made by gluing two squared edges as in a plain edge joint or by using machined joints of various kinds.
  • End Joint – A joint made by bonding two pieces of wood together, end to end, commonly by finger or scarf joint.
  • Fingerjoint – An end joint made up of several meshing wedges or fingers of wood bonded together with an adhesive. Fingers are sloped and may be cut parallel to either the wide or narrow face of the piece.
  • Lap Joint – A joint made by placing one member partly over another and bonding the overlapped portions.
  • Scarf Joint – An end joint formed by joining with adhesive the ends of two pieces that have been tapered or beveled to form sloping plane surfaces, usually to a featheredge, and with the same slope of the plane with respect to the length in both pieces.
  • Starved Joint – A glue joint that is poorly bonded because an insufficient quantity of adhesive remained in the joint.
  • Sunken Joint – Depression in wood surface at a joint caused by surfacing material too soon after bonding.

The craft of connecting and securing the separate members of the timber frame to one another by means of specific cuts on the ends and/or sides of the timbers.


Part or the arrangement of the part, where two or more timbers are joined together.

Jointed (JTD)

In lumber manufacture, finger-jointing is most common although sometimes other types of joints may be used.


A piece of lumber two to four inches thick and six inches wide, used horizontally as a support for a ceiling or floor. Also, such a support can be made from aluminum, steel, or other materials.

Joists and Planks (J&P)

The national grading rules contain four grades of structural joists and planks; select structural, No. 1, No. 2, and No. 3. Nominal sizes are 2 to 4 inches thick by 5 inches and wider. The abbreviation (J&P) in generally used to indicate a specific section in the grading rules under which the lumber was graded.


One who logs and sells his output on the open market; not associated with a mill or under a company/dealer contract.

Joist Hanger

A pre-manufactured metal piece typically attached to a ledger or to beam to support a joist. Joist hangers should be galvanized.


A hydraulic control lever that can be operated in up to four directions, controlling a number of functions through one hydraulic valve.



Juvenile Wood

The wood in every tree that forms within its first 10 years or so; usually has undesirable characteristics such as low strength and shrinkage along the grain.

Woodipedia Index A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
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