Window Parts Glossary

If you don’t work in the window industry, you might find the terminology a bit confusing.  There are names for window parts that you don’t often hear in everyday conversation.  This can make for a “communications gap” when homeowners talk with window sellers and installers. 

To help bridge that gap, we present our Window Parts Glossary for our two most popular types: Double Hung and Casement windows.  It should come in handy if you ever need to purchase parts or order replacement windows. 


Window Parts on Double Hung Windows


Typically this is a spring-loaded device that serves as a counterbalance against the weight of the sash.  It helps the sash to open and close easier.

Check Rail

This is the place where the upper and lower sashes come into contact when the window is closed. 

Fixed Panel

A panel that contains glass but does not open or close.


This is the material that surrounds the outside of the entire window construct.  It supports the entire system and holds it together. Without it, you would have a collection of parts that weren’t together. 


These are decorative lines on the pane of glass that give the appearance of multiple panes.


This is the horizontal piece that makes up the top of the frame.


These are the two vertical pieces that make up the sides of the frame. 


The handle used for opening and closing the window. 


This is a horizontal piece that brings two or more windows together.  It is essential for adding structural integrity to the combined window system.


The upper and lower horizontal pieces of a window sash.


This is the horizontal piece that makes up the bottom of the frame. 


This is the moveable part of the window that holds the glass.

Weep Hole

These are holes in the window sill that allow water to drain outside.


Window Parts on Casement Windows

Aluminum Clad

This refers to extruded aluminum that covers the exterior wood parts of a window to protect it from the elements.


A gas used between panes of glass to insulate the window and make them more energy efficient. Argon is a nontoxic, inert gas.


This is a decorative molding that covers the space between the wall and the window frame.


This is a crank-mechanism used to open and close the window.

If you have questions about replacement windows or parts, call Liberty Window today at 888-645-9479.