Published Jun 19, 2019 9:16:36 AM

A Quick Guide to Doorglass Terminology

While “doorglass” may seem like a self-explanatory term, there’s a lot of nuance in the language that the building industry uses to talk about it. Many people may not even be aware that there are industry terms for doors with glass panels or door windows, which can be frustrating when trying to update the look of your entryway. These ten terms—with a few clarifiers—will help you find exactly what you’re looking for in your door.

Foundational Terms

1. Doorlight

The term doorlight refers to a door component composed of a glass panel with a frame that is inserted and fastened into a steel, fiberglass, or wood door, sidelight, or transom.

Doorlights can use glass that is decorative or clear and is usually insulated to help regulate inside temperatures and promote energy efficiency. They are usually inoperable, or fixed, as opposed to operable windows that can be raised, lowered, or swing out depending on the type of window. This is important for both security, insulation, and weather protection on exterior doors.

Doorlights come in a variety of sizes and shapes. Full lights, three-quarters, half lights, and quarter lights are so named because they occupy the full length, three quarters, top half or top quarter of the door, respectively. Within those sizes are a variety of shapes and doorglass configurations that match certain residential and architectural styles, regional designs, and personal preferences.

Doorlight is also frequently spelled door light, door lite, and door-lite. All these terms refer to the same thing.


2. Sidelight

A sidelight is a fixed glass panel with a frame that is mulled, or installed, on one or both sides of an exterior door.

Sidelights, like doorlights, can consist of decorative or clear glass in a variety of sizes. They are similarly insulated and secure, and can be used in conjunction with matching doorlights, or with a door that doesn’t have a light for additional style and natural light in the home. Often, they are used to make the entry door look larger, brightening the entryway and increasing curb appeal.



3. Transom

A shortened form of transom window, a transom is a glass panel with a frame that is installed above a door. 

Transoms are most commonly fixed due to their hard-to-reach nature, though operable transoms do exist to promote airflow. Like sidelights, transoms are decorative elements in the entrance of a home that give the illusion of a large entry door and bring natural light into the home. The most common transom shapes are rectangular, elliptical, segment head, and round.


4. Insulating Glass (IG)

Commonly known as double glazing or triple glazing, insulating glass (IG) consists of either two or three panes of glass that are separated by a vacuum or a space filled with argon, krypton, or xenon. Spacers made of aluminum or foam separate the panes of glass in insulating glass units (IGUs). IGUs are used to reduce heat transfer, improve energy efficiency, and reduce sound transmission. 


Helpful Terms

5. Caming

In decorative glass, caming refers to the metal work that joins together the glass elements. Also known as doorglass finishes, or the “lead” in “leaded glass,” caming can be a variety of materials, colors, and widths to match door hardware and outdoor fixtures. 


6. Divided Lights

Referring to doorglass and windows in which the glass is sectioned into more than one part, divided lights feature prominently in residential styles such as Colonial, Prairie, Arts & Crafts, and Tudor.


Muntins are the dividers in a divided light. Traditionally, muntins referred to a verdical divider in building, and were used to help bear the weight of a large window for structural security. Today, improved building materials and processes make load-bearing muntins unnecessary, and they are primarily used to achieve an aesthetic. 

Because it is pronounced the same way as “mutton,” the word muntin is often spelled incorrectly. 


A grille is a decorative element that mimics a muntin, giving a panel of glass in a doorlight, sidelight, transom, or window the appearance of a divided light. Grilles, sometimes referred to as bars, are typically made of aluminum, plastic, or another lightweight material, and can be internal (between glass panels) or external.

Grilles Between Glass (GBG)

Grilles Between Glass, abbreviated to GBG, is a style of doorlight, sidelight, or window that consists of internal grilles between two panes of glass. This popular style emulates the look of a divided light but is much easier to clean. 

See our colors and configurations of Grilles Between Glass. 


True Divided Lights

True divided lights, sometimes referred to as authentic divided lights, recreate traditional doorlights and windows with improved materials and insulation. A nine light door, or a door with nine sections of glass, would therefore have nine separate panels of glass. 

Simulated Divided Lights (SDLs)

Simulated divided lights, abbreviated to SDLs, achieve the look of a true divided light while maintaining the superior energy efficiency of having a single, large IGU. Some SDLs incorporate an internal grille to give the appearance of a muntin in a true divided light, while others use only external bars or grilles. 


7. Exterior Door

Simply put, exterior doors are any door that allows passage between the interior and exterior of a home. This may include front doors, service doors, and patio doors, both sliding and French.

Slab Door

A slab door is a piece of fiberglass, steel, or wood with the finished dimensions of your door but otherwise unprepared for installation. It lacks hinges, hardware, and a frame. Unfinished doors are also unpainted or unstained, without any treatment to protect against outdoor wear and tear. In order to install doorlights into a slab door, you must first cut an opening. 

Prefinished Door

Prefinished doors are painted or stained, treated, and have any doorlights pre-installed. They still require hardware and a frame prior to installation in your home, but reduce the labor and time required by unfinished slab doors. 

Pre-hung Door

Pre-hung doors are purchased with all necessary components completed—paint or stain, treatment, hardware, frame, and doorlights. All that’s required is to install it into your home. 

Screen & Storm Doors

Installed in front of an exterior door, screen doors and storm doors provide opportunities for ventilation and additional protection from bugs, allergens, and weather.

Paneled & Flush

Paneled doors, also known as stile-and-rail doors, contain panels that vary in dimensions and quantities by region. These panels can be raised or flat, with numerous sticking profiles, which are the pieces around the border of the panel that hold the panel in place. This allows for a huge variety of designs for paneled doors, making them a versatile and attractive option for many architectural styles.

Flush doors are simple, consisting of two flat faces on either side with no decoration or ornamentation. They are more common for interior doors than exterior and are frequently seen in modern or contemporary designs.


Smooth & Wood Grain

Depending on the material that the door is made from, there are two primary textures: smooth and wood grain. Steel doors are typically smooth and wood doors retain their natural wood grain patterns unless covered by another material. Fiberglass doors can be either smooth or wood grain. Smooth doors are usually painted, while wood grain doors are often stained to maximize the effect of the natural texture.


8. Glazing

Glazing, from the Middle English word for glass, is both a noun and a verb. One refers to the glass in a window or door. The other is the act of installing or replacing glass. While not commonly used on its own, the phrases double-glazing and triple-glazing both derive from this term. 


9. Low-E Glass

Low emissivity, or low-e, glass is clear glass with a thin, transparent coating that reflects heat. This reduces heat transfer from outside the home in hot weather, and from inside the home in cold weather. 

Used in IGUs, low-e glass improves the energy efficiency of a home by reducing heat transfer at exterior doors and windows, where most heat transfer occurs. The coating is microscopically thin, but may look slightly more blue or green than clear glass without low-e coating.

There are two types of low-e coatings: hard coat and soft coat. Hard coat low-e glass is made by applying various metals, primarily tin, to molten glass. Soft coat is applied to the glass through a process called sputtering, which spreads silver or a mixture of silver and other metals to the surface of the glass. In an IGU, the surface of the glass with a soft coat low-e coating faces inward, which prevents the coating from rubbing off or oxidizing. Hard coat low-e coatings absorb more heat than soft coat, making soft coat the more energy efficient option.


10. Safety Glass

There are three types of safety glass that are relevant to doorglass: tempered, laminated, and severe weather. 

Tempered glass is a type of safety glass that crumbles, rather than shatters, when broken, and is therefore less likely to cause injury. 

Laminated glass consists of two or more panes of glass with a vinyl interlayer.  

Severe weather glass is designed for hurricane zones and other high-wind areas to resist shattering, even when hit directly with wind-borne objects. 

Learn more about ODL Severe Weather doorglass here.

All glass inside of or near a door must be safety glass, with exact definitions of ‘near’ determined by local building codes. 


This short guide to doorglass terms and phrases covers some of the most common words you may encounter, but there’s plenty left to learn. Subscribe to the ODL blog by entering your email to the right to get new articles delivered to your inbox. You can also explore different types of doorglass with the ODL Doorglass Selector, which allows you to see different styles, sizes, and designs with filtering options. 

Explore ODL Doorglass


Traditional Simulated Divided Lights (SDL)

A mill finish grille between glass with our all-in-one SDL frame provides the look of a true divided light with the energy efficiency of a single light.

Learn More Where to Buy

Clear Glass

When you want the view and nothing but the view, Clear Glass is your answer. It is an option that works equally well from your entry door to your patio door. Offered in Clear and Low-E for standard 6/8 and 8/0 door sizes, the breadth of options for your doors, sidelights, and transoms means choices that fit your home.

Learn More Where to Buy

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