J

Jack Rafter

A rafter that spans the distance from the wall plate to a hip, or from a valley to a ridge.

Jalousie

A type of window consisting of a number of long, thin, hinged panels.

Jamb

The side and head lining of a doorway, window, or other opening.

Joist

A horizontal structural member, which supports the floor or ceiling system.

Junction Box

An electrical box used for wire splicing.