Keeper - The metal latch plate in a door frame into which a doorknob plunger latches.

Kerf - The void created by the width of a saw blade as it cuts.

Keyless - A plastic or porcelain light fixture that operates by a pull string. Generally found in the basement, crawl space , and attic areas.

Keystone - The central, topmost stone of an arch.

Keyway - A slot formed and poured on a footer or in a foundation wall when another wall will be installed at the slot location. This gives additional strength to the joint/meeting point.

Kick Plate - A protective plate mounted on the bottom of a door to prevent damage to minimize damage to the door.

Kiln - A heating chamber for drying lumber.

Kiln Dried Lumber - Lumber that has been properly dried and cured (to 15 percent moisture content) resulting in a higher-grade lumber than air-dried.

Kilowatt (kw) - One thousand watts. A kilowatt hour is the base unit used in measuring electrical consumption. Also see watt.

King Post - In a roof truss, the central upright piece.

King Stud - The vertical "2 X's" frame lumber (left and right) of a window or door opening, and runs continuously from the bottom sole plate to the top plate.

Knee Wall - A wall supported by jack studs in half- story construction.

Knob and Tube Wiring - A wiring system used before 1945. Two strands of copper wire are run along framing by connecting them to porcelain knobs and through framing inside porcelain tubes.

Knockout - A removable piece of an electrical box or panel that's "knocked out" to allow cable to enter the box.

Knot - In lumber, the portion of a branch or limb of a tree that appears on the edge or face of the piece.