The Drawing above is a complete Double Hung Wood Window Unit which consists of One Frame and two Sashes. The Sashes move up and down and the Frame holds the Sashes in place. 

Apron:  A piece of interior trim that fits under the Stool. (Usually the same size as the interior casing)

Blind Stop:  Pieces of wood that fit on the outside of the Window Frame and holds the Outer Sash in place.

Brickmould:  The outer casing on a window that usually fits against the brick on the exterior of a building.

Head Jamb:  The top horizontal part of a Window Frame.

Inner Sash:  Also known as the Bottom Sash is the part of a Double Hung Window that holds the glass in place and moves up and down.

Interior Casing:  The decorative trim that goes on the inside of a building. (On both sides and top of the frame)
 
Interior Stop:  Usually a small piece of trim that fits on the inside of the Window Frame and holds the Inner Sash in place.
 
Lock:  The part of a window that keeps the Inner and Outer Sashes from moving up and down for security.

Meeting Rail:  Also known as check rail helps the Inner and Outer Sashes meet together and become weatherproof.

Muntin:  Also known as Muntin Bar (Bars are the vertical muntins) fits inside of a sash to hold the glass in place if there are more than one piece of glass in the sash. (This is known as TDL or True Divided Lites)

Outer Sash:  Also known as the Top Sash is the part of a Double Hung Window that holds the glass in place and moves up and down.

Parting Strip:  Also known as Parting Stop and Parting Bead. Pieces of trim usually 1/2 x 3/4 that fits between the Inner and Outer Sashes to hold them in place. 

Rail:  The horizontal parts of the Window Sashes. (Top Rail, Bottom Rail, Meeting Rail)

Side Jamb:  The side vertical parts of a Window Frame.

Sill:  The angled bottom part of a Window Frame that helps direct water away from the building.

Stiles: The side vertical parts of a Window Sash.

Stool:  A flat piece of trim that goes on the inside of a building on top of the Sill and Apron also fitting against the inside of the Bottom/ Inner Sash.

​Caldwell Sash Company LLC
6020 Scottsville Road
Floyds Knobs, IN 47119
​502-931-0224