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Window Terminology

# FAQ
11 min read
  • 06 February, 2023
INTRODUCTION

This article illustrates the most common terms used to describe the parts of windows and glazed doors compiled from the AGWA Window Terminology document which can be found in the Downloads section.

WINDOW AND DOOR FRAME

The frame is common to all doors and windows. It is the supporting structure of a window or door. The parts are illustrated on a generic window frame in Figure 1.2.


Figure 1.1 Generic Window

Figure 1.2 Window Frame Elements, Expanded

1. Head: All horizontal members at the top of the window or door frame.
2. Jamb: The vertical sides of the window or door frame
3. Mullion: The vertical framing members between window units.
4. Transom: A horizontal intermediate framing member of a window assembly.
5. Sill: The horizontal member at the bottom of the window or door frame (see Note).

Threshold: The horizontal member at the bottom of the door frame (see Note).

NOTE: The bottom member of a door frame can sometimes be referred to as the threshold instead of the sill. The names of all other framing members can be used interchangeably for window and doors.

WINDOW SASH

A window sash is the inner frame which holds the glass in the operating or fixed part of the window.

1. Top Rail: Top member of the sash.
2. Stile: The vertical members of the sash.
3. Bottom Rail: The bottom member of the sash.
4. Sash Light: The glass fitted within the sash.
5. Fixed Light: Glass in the non-operable units of the window. In some cases, this is set directly into the frame.

In a double hung window (Figures 2.2 and 2.3), there are two sashes. The sash members that meet
when the window is closed are called the Meeting Rails 6.


Figure 2.2 Double Hung Sash, Closed.

Figure 2.3 Double Hung Sash, Open.
SLIDING DOOR PANEL

Doors use slightly different terminology. While the terms used for the parts of the frame are nearly the same there is no longer a Sash. Instead they have a Panel which is a surround separate from the frame. Both the moving and non-moving parts of a sliding door are called panels.


Figure 3.1 Generic Sliding Door

Figure 3.2 Sliding Door Elements, Expanded

1. Opening Panel: The panel of a sliding door that moves (boundary shown by red line).
2. Fixed Panel: The panel of a sliding door that does not move (boundary shown by red line).
3. Top Rail: Top member of the panel.
4. Fixed Panel Top Rail: The top member of the fixed panel.
5. Lock Stile: The stile of the opening panel that engages with the jamb. Fitted with the door lock.

6. Interlock Stile: The stiles on the fixed and moving panels that engage with each other when the door is closed.
7. Fixed Panel Stile: The stile of the fixed panel that engages with the jamb.
8. Bottom Rail: The bottom member of the panel.
9. Panel Glass: The glass within door units.

FRENCH DOOR PANEL

French doors use the same terminology as for sliding doors but without the interlocking stile.
Instead, the stiles that meet in the middle are called Meeting Stiles 3.


Figure 4.1 Generic French Door

Figure 4.2 French Door Elements, Expanded

French doors do not have a mullion which, for other doors and windows, provides structural strength. This makes French doors completely reliant on the fixings back into the frame to give them support. Due to this, they are often restricted in size.

1. Top Rails.
2. Stiles.
3. Meeting Stiles.
4. Bottom Rails.
5. Panel Glass.