Glass Window Glossary: Identifying the Parts of Windows

Worker is installing a corner window

What are the parts that make up a glass window? You may have heard of the window pane and window sill, but many other components are a part of the finished product.

All the lingo and the terms can get confusing, so Springfield Glass Company is here to help. 

Here’s our glass window glossary with all of the basic window terminology you need to know.

The next time you’re out shopping for windows, this glossary can serve as your guide.

The #1 Most Important Thing You Need to Know About Window Glass

Windows have two sheets of glass, separated by a space that’s filled with gas or air. So when a window breaks, you can’t take out that piece of glass, you have to remove both glass panes. That’s partly why window glass replacement services are so expensive.

Window Frame

The window frame consists of the sill, head, and jamb. It’s usually made of wood or vinyl. The sill is the lowest part of the frame, while the head is the highest. The jambs are the vertical sides of the frame. 

Related Post: Different Types of Window Glass

Casing and Trim 

The casing and trim describe the decorative wood that surrounds the perimeter of the window. It covers the space between the wall and the frame.  

Window Glass 

Window glass is that clear material within the window frame. Did you know that window glass is made from silica, the same stuff as sand on the beach? You can read more about window glass edge types by visiting our various blog articles. 

Window Glass Components

A variety of components hold the window glass together. These components may vary depending on the type of glass and window. Once you understand the basics, you can find the exact window part you need.  

Related Post: How to Eliminate Condensation Inside Windows  

  • Pane – A pane is a single sheet of glass.
  • Sash – The sash is the movable part of the window that holds the glass panes together. The sash fits inside your window frame.   
  • Mullion – The terms mullions and muntins often get confused. A mullion is a vertical post or bar that separates window units. Mullions are mostly a structural element, but they can be decorative features in some styles.  
  • Muntins – A muntin is the framing used to separate and hold glass pieces within a window. Muntins (AKA, “Grilles”) are typically made of metal or wood.  
  • Check Rail – Also known as the middle of the window; the check rail is where the sashes of each window meet on double-hung windows.   
  • Jamb – The vertical parts that form the sides of a window frame.
  • Casing – Moldings that go around the window frames, often installed outside to seal the window frame to the house’s framework.
  • Apron – A decorative trim installed beneath the railing or sill.
  • Head – The highest part of a window frame.
  • Sill – The lowest part of a window frame.

The Supportive Parts of a Window

Without supporting parts, most windows just aren’t functional:

  • Weather Stripping – Weather stripping windows with a waterproof, air-tight seal is an absolute MUST (vinyl, felt, metal, or rubber stripping materials are common).
  • Screen – This is a fine mesh (fiberglass or aluminum) that’s used to keep pesky bugs out of the home.
  • Balance – counterbalance weight is often used to keep single- and double-hung windows open.
  • Window Film – a scratch-resistant polyester film can be applied to window glass to reduce and reflect UV light.
  • Weep Hole – A small opening near the bottom of the exterior frame that drains water and condensate from windows.

Expert Window Installation Services at SGC

Springfield Glass Company offers window replacement and installation services for your home or business. We’ve provided first-rate glass products and professional service for over 30 years. If you live or work in Springfield or the surrounding areas, give us a call. Call 417.883.6555 today, and we’ll give you a free estimate on our window glass installation services.

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