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Parts of interior door: all you need to know about the anatomy of a door

Parts of interior door: all you need to know about the anatomy of a door

Changing your interior doors is one of the simplest ways to improve your home's curb appeal. However, with the myriad of designs available in the market, it is not uncommon to get confused over which solid wood interior doors to pick. 

Knowing the anatomy of a door is a surefire way to simplify the purchasing process. As such, this article lists all the basic parts of door, clearly explaining their functions for easier understanding. With such knowledge, you can easily explain to manufacturers and contractors the type of door you want and your preferred features.

Door frame (casing)

This is the framework or enclosure that holds the door into place when attached in place. It is part of the anatomy of a prehung door, with many manufacturers building it from wood, fiberglass and aluminum.

The door frame consists of other parts including:

  • Sill: the bottom part of the frame that holds the vertical frames in place, while also preventing dust and pests from accessing a room. In most cases, you will find them on doors that lead to the home's exterior.
  • Jambs: there are two types of jambs namely: the door and head jambs. The former are the two frames that run from top to bottom. They attach to the walls and offer support while facilitating door opening. The latter is the horizontal piece that sits at the top of the frame.

Door Panels

These are slabs that make the entire door. They are the rectangular slabs that are placed between the rails and stiles.


These are the metals that attach the casing to the bedroom door (or any other interior door for that matter), allowing it to swing from one side to the other.


These pieces are parts of the actual door. They are placed from left to right across the door at the uppermost and bottommost sections. Sometimes, manufacturers will also add an extra piece at the midsection.


These are vertical pieces on both edges of a door, and are one of the most crucial components of a door. There are two types of stiles namely;

  • Lock stile: which is the piece that runs from top to bottom at the edge where the locks and the latch are mounted.
  • Hinge stile: the piece that runs from top to bottom at the edge where the hinges are mounted.


Some houses will have doors joined to windows or sidelights. In this case, the seam where the door and window frames meet is called the mullion.


This is a piece of narrow glass placed on the side of a door. Its sole purpose is to improve a home's illumination, which is one of the reasons why many homeowners will prefer having it not only on one side but both. Apart from bringing in more natural light, many architects will recommend it to improve a home's curb appeal.


This is a component that is placed on top of the sill. It is one of the most vital door structure parts as it keeps the doors weathertight. Since they act as the sill's protective cover and people will often step on them, they are manufactured from high-quality metals such as aluminum and bronze. 


These are only a few parts of an interior door that every homeowner should know about. We hope that this guide helps you name parts of a door with ease.

However, if these terminologies are still hard to decipher, United Porte experts are here to help you. We are dealers in flush, french, bi-fold, panel, pocket interior doors, you name it!

Contact us today to find your home’s ideal door.

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