Keeper- The metal latch plate in a door frame into which a doorknob plunger latches.
Keyless- A plastic or porcelain light fixture that operates by a pull string. Generally found in the basement, crawl space , and attic areas.
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.
Kilowatt (kw)- One thousand watts. A kilowatt hour is the base unit used in measuring electrical consumption. Also see watt.
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.
Knot- In lumber, the portion of a branch or limb of a tree that appears on the edge or face of the piece.