Door Terms to Know: Replacement Door Terminology Guide
When it comes to replacing a door, knowing the right terminology can make all the difference. Whether you're speaking with a contractor, browsing styles online, or comparing estimates, being familiar with door parts, styles, and frame components can help you make more informed decisions. It can also help you avoid confusion between similar or outdated terms that are still used today.
This helpful guide will walk you through the most common (and often misunderstood) door terms to know, including the proper names of door parts, common styles, and frame components. Understanding this replacement door terminology not only makes conversations easier, it ensures you feel more confident in your home improvement choices.
Why Door Terminology Matters
Whether you're choosing a stylish new entry door, replacing aging interior doors, or upgrading your patio doors for better energy efficiency, knowing the correct terms helps you:
- Understand your options
- Communicate clearly with your installer
- Spot quality features
- Avoid misunderstandings during installation or purchasing
Let’s break down the essential door parts and terms you should know.
A–Z of Common Door Terms to Know
Astragal
A vertical strip attached to the edge of one of a pair of doors to cover the gap between them. Common on French doors for improved insulation and security.
Bore Hole
The hole drilled into a door to fit the lockset or doorknob.
Brickmould
A type of exterior trim around a door or window. It covers the gap between the door frame and wall for a finished look.
Casing (Interior Trim)
The decorative molding or trim that covers the edge between the wall and the door frame on the interior side.
Core
The interior material of the door slab. Can be solid (better insulation and soundproofing) or hollow (lightweight and economical).
Door Jamb
The vertical parts of the door frame that the door attaches to via hinges on one side and the strike plate on the other.
- Side Jambs: The vertical pieces on the sides.
- Head Jamb: The horizontal top piece of the frame.
Door Lite
A window built into a door. Styles range from small decorative glass panes to full-length glass panels.
Door Slab
Just the door itself—no frame, hinges, or hardware.
Double Door
Two doors hung side-by-side within the same frame. Often used at front entrances or patios.
Flush Door
A smooth-surfaced door with no panels or decorations. Typically used for interior doors.
French Doors
A pair of doors that feature multiple glass panes, often opening outward or inward to a patio.
Hinge
A mechanical bearing that connects the door to the frame, allowing it to swing open and closed.
- Butt Hinge: Most common hinge style.
- Concealed Hinge: Hidden within the door, often found in modern or minimalist designs.
Inswing / Outswing
Indicates the direction a door opens. An inswing door swings inward; an outswing door swings outward.
Lite
Refers to a glass pane within the door. You’ll often see terms like “half-lite” or “full-lite” to describe how much of the door is glass.
Lockset
The locking hardware that includes the latch, knob/handle, and locking mechanism.
Mullion
A vertical or horizontal bar between door panels or between a door and a sidelight.
Panel
A raised or recessed section of the door slab. Doors are often categorized by the number of panels they have (e.g., six-panel door).
Prehung Door
A door that comes already mounted into a frame, making it easier to install as a complete unit.
Rails
The horizontal parts of a panel door:
- Top Rail
- Bottom Rail
- Lock Rail (the rail at handle height)
Rough Opening
The framed opening in the wall where a door or window will be installed. This is larger than the actual door to allow for adjustment.
Sidelight
A vertical window on one or both sides of a door. Adds light and architectural appeal to entryways.
Sill
The bottom part of the door frame, where the door rests when closed. Often confused with the threshold, which is the plate or strip the door closes against.
Slab Door
Same as a door slab, just the panel without the frame or hinges. Great for replacing a door in an existing frame.
Stile
The vertical pieces on either side of the door slab, forming the outer edges.
Strike Plate
The metal plate attached to the door jamb where the latch or deadbolt enters when the door is closed.
Sweep
A flexible strip attached to the bottom of the door to block drafts, dust, and insects.
Threshold
Often confused with a sill, the threshold is the piece that covers the sill and provides a seal between the door and floor.
Transom
A window located above a door, usually decorative or for letting in additional light.
Weatherstripping
Material applied around the door frame to create a seal and improve energy efficiency.
Confusing or Overlapping Terms
Many door terms sound similar or are used interchangeably. Here are a few to watch for:
- Slab vs. Prehung: A slab is just the door; prehung includes the frame.
- Threshold vs. Sill: The threshold sits on top of the sill and is often the visible part.
- Jamb vs. Frame: The jamb is part of the overall frame, but people often refer to the whole assembly as the frame.
- Lite vs. Panel: A lite is made of glass; a panel is wood, composite, or another solid material.
Knowing the correct names of door parts helps reduce mix-ups when ordering or installing.
Choosing the Right Door Starts with the Right Team
At Morgan Exteriors, we know that replacing a door isn't just about improving looks—it's about improving security, energy efficiency, and comfort too. Our experienced team will walk you through every option and explain all the door terminology so you feel confident in your choices.
Whether you want a full-lite fiberglass entry door, beautiful French doors to open up your patio, or a classic panel-style door with modern upgrades, we make sure you understand the differences—and find the right fit for your home and budget.
Get Expert Help with Your Door Replacement
Still not sure what type of door you need or which door parts matter most? That’s exactly why homeowners throughout Florida trust Morgan Exteriors. We provide:
- Free door consultations and estimates
- Energy-efficient, hurricane-rated doors
- Professional installation by trained technicians
- Honest guidance with zero pressure
Ready to Upgrade Your Door?
Contact Morgan Exteriors today to schedule your free estimate and see how easy it is to boost your home’s style and security with the right door, explained in plain language, not jargon.
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