Door Terminology Explained For Homeowners

When a joiner hands you a door specification, terms like jamb, escutcheon, raised and fielded panel and multi point lock appear without explanation. Most homeowners nod along and hope the result will match what they had in mind.

This glossary of door terminology changes that. It covers the main door styles, how a frame and leaf are constructed, glazing options, hardware and security terms, and the materials and finish details that determine how long a door lasts. Use it to find the door terms you need before a conversation with your joiner, or to make sense of a quote that has arrived full of words you did not recognise.

Door Styles

Before anything else, it helps to know what type of door you are dealing with. The style shapes everything that follows: the frame configuration, the glazing layout, the hardware, even how the door feels to use every day. Here are the most common types.

Front Door

A front door is the main entrance to a property and, in most cases, the detail people notice first. It sets the tone for the whole building, which is why the specification matters more here than on any other door in the house. Front doors come in a wide range of materials including timber, aluminium, uPVC and composite, and in styles that run from traditional panelled designs with period ironmongery to fully glazed contemporary entrances.

At Turner & Co, our bespoke timber front doors are handcrafted to the exact requirements of the property and the client. Panel layout, glazing configuration, moulding profile, hardware and finish are all chosen to suit the building and the brief, with everything made to measure in our Ipswich workshop.

French Doors

French doors are a pair of glazed doors hung from opposite sides of the frame, opening outward from the centre with no fixed mullion between them. They are most commonly used to connect a living space to a garden, patio or terrace, and their full height glazing brings in a generous amount of natural light. On a sunny afternoon with both leaves folded back, they effectively remove the wall between inside and out.

Our handcrafted timber French doors are made to measure with high performance glazing, and are available in configurations to suit both period and contemporary properties.

Stable Door

A stable door is divided horizontally into two independent halves, upper and lower, each hung separately so either can be opened independently of the other. Open the top half for light and air, keep the lower half closed to stop the dog getting out. Simple, practical, and on the right property, genuinely charming.

The style suits cottages, farmhouses and any house where the kitchen or utility room opens onto a garden. Our timber stable doors are handcrafted from quality timber, fitted with durable hardware and secure locking systems, and finished to your specification.

Bi Fold Door

A bi fold door is made up of two or more panels that fold back against each other on a track, clearing the full width of the opening when open. On a large opening to a garden or terrace, the effect is dramatic. The room simply opens up. Bi fold doors are available in timber, aluminium and uPVC.

Our bespoke timber bi fold doors are built from quality sustainably sourced timber for strength and stability, fitted with high performance glazing and durable spray finishes, and made to your exact measurements.

Sliding Door

A sliding door moves horizontally along a track rather than swinging into or out of the room. Where a swinging door would eat into the space behind it, a sliding door takes nothing. The panel just disappears to one side. This makes sliding doors particularly popular on larger glazed openings to gardens and in contemporary interiors where clean lines matter.

Sliding doors come in timber, aluminium and glass. At Turner & Co we specialise in handcrafted timber doors.

Pivot Door

A pivot door hangs on a top and bottom pivot point rather than side hinges, which means it rotates from a point offset from its edge rather than its corner. Open it and half the door swings one way, half swings the other. It is a distinctive effect that looks particularly striking on wider and taller doors. Pivot doors are most associated with contemporary architecture and high specification residential projects, and are typically made in steel, aluminium or glass.

Timber pivot doors are possible but the weight and mechanism require careful structural thought. Worth a conversation with your joiner before committing to the design.

Composite Door

A composite door is built from a combination of materials, typically a timber or steel subframe, an insulating foam core and a glass reinforced plastic facing. The result holds its shape reliably in changing weather conditions and needs very little maintenance, which is why composite doors are popular with homeowners who want an easy life at the front of the house.

The trade off is that no manufactured skin quite replicates the depth and warmth of real timber. A well made bespoke timber door, properly finished, will outlast most composite products and look considerably better doing it.

Pocket Door

A pocket door slides into a cavity built into the wall beside the opening, disappearing completely when open rather than sitting on a surface mounted track. When you need a clear opening with no door in the way, between a kitchen and a living room for instance, or in a tight hallway, a pocket door solves the problem neatly. They are typically used internally and come in a range of materials and finishes.

Frame And Structure

The frame is the fixed structure the door sits in. Every other term in this section refers to a part of it, so getting these names straight first makes everything else easier to follow.

Frame

The frame is the fixed outer structure secured to the wall of the building. It carries the weight of the door, holds the opening square and provides the surface the door closes against. In a timber door, the frame has four parts: the head at the top, the cill at the bottom, and the two jambs running vertically on each side.

Head

The head is the horizontal member at the very top of the frame. It spans the full width of the opening and takes the structural load from the wall above.

On a door with a fanlight, the head sits between the door opening and the glazed panel above it, forming the dividing line between the two.

Jamb

The jambs are the two vertical members running up either side of the frame. The hinge jamb is the side the door is hung from. The latch jamb is the side it closes against, where the strike plate sits.

If you ever need to tell your joiner where a draught is coming from or where the door is catching, jamb is the word you want. Left jamb, right jamb. Either way your joiner knows exactly where to look.

Cill Or Sill

The cill, sometimes spelled sill, is the horizontal member at the very bottom of the frame on the outside of the building. It is shaped to shed rainwater away from the door and keep water from getting under the threshold.

The cill takes more punishment from the elements than any other part of the frame. It is one of the first things worth looking at closely in any specification.

Threshold

The threshold is the strip running across the bottom of the door opening at floor level, bridging the gap between the door and the floor. It seals against water, draught and debris when the door is closed and creates a smooth transition between inside and outside floor levels.

On an external door, the threshold, cill and bottom weatherseal work as a team. If any one of them is poorly specified, you will know about it the first time it rains hard.

Sill And Threshold: What Is The Difference?

The cill is the structural component at the base of the frame, fixed to the building and part of the outer frame. The threshold sits on top of it inside the opening and provides the weatherproof seal and floor transition. The cill is part of the frame. The threshold is what you step over.

Fanlight

A fanlight is a glazed panel above the door, set within the frame or in a separate section directly above it. The name originally described a semicircular panel with radiating glazing bars shaped like a fan, a feature associated with Georgian architecture and still one of the most elegant details on a period entrance.

Today the term covers any fixed glazed panel above a door that brings light into the hallway. On a Victorian or Georgian property, the glazing pattern in the fanlight is often as important to the character of the entrance as the door itself.

Sidelight

A sidelight is a narrow vertical glazed panel beside the door, set into the frame on one or both sides. It brings more light into the entrance without making the door itself wider. Sidelights can be fixed or openable.

On a period property they are usually part of the original design. On a renovation, adding sidelights is one of the most effective ways to deal with a dark hallway, often more effectively than changing the door itself.

Architrave

The architrave is the decorative moulding that runs around the door frame on the interior wall face, covering the joint between the frame and the plaster. Without it, you would see a gap or a raw edge where the frame meets the wall.

On a period property, the architrave profile, whether it is an ogee, a torus, a plain chamfer or something more elaborate, is one of the details that determines whether the door feels like it belongs in the room or arrived from somewhere else.

The Door Leaf

The leaf is the part that moves. Everything else is fixed. Once you understand how a leaf is put together, stiles on the sides and rails running horizontally with panels filling the spaces, you can read any door drawing without guessing.

Leaf

The leaf is the moving panel of the door itself. A single door has one leaf. French doors have two. The term distinguishes the door panel from the frame it hangs in, which matters when a drawing or specification is describing dimensions or faults.

Stile

The stiles are the two vertical members running up either side of the door leaf, forming the outer edges. The hinge stile carries the hinges and takes the full weight of the door through its swing. The latch stile is the closing edge, where the lock hardware sits.

Knowing the word stile gives you precise language. Left hand stile, bottom third, and your joiner knows exactly where to look.

Rail

Rails are the horizontal members of the door leaf. Most doors have a top rail, a bottom rail, and one or more intermediate rails between them. The rails and stiles form the outer structure and divide the leaf into sections for panels or glazing.

On a traditional timber door, the number and position of the rails is what gives the door its character. A two panel door reads very differently from a six panel one.

Top Rail

The top rail runs across the very top of the leaf, connecting the two stiles and framing the uppermost section of the design. It contributes significantly to the rigidity of the door.

Bottom Rail

The bottom rail runs across the very bottom of the leaf. On an external timber door it is typically wider than the other rails, providing enough material at the base to house the weatherseal and threshold hardware without the door becoming fragile at the point it gets the most contact.

Frieze Rail

A frieze rail is an intermediate horizontal rail at roughly eye height on a traditional panelled door. It divides the door into an upper section, usually glazed or decoratively panelled, and a lower section that is typically solid timber. Not all doors have one, but on a four or six panel door it is usually what separates the glass lights above from the solid panels below.

Middle Rail

A middle rail sits roughly in the centre of the leaf, dividing it into equal upper and lower halves. It is a common feature on traditional two and four panel doors.

On a stable door, the middle rail is where the door splits. Everything above it and everything below it hangs independently from the frame.

Mullion

A mullion is a vertical structural member dividing the leaf into two or more sections side by side. On a door with a central glazed light flanked by solid panels, it is the mullion that creates the division. It is structural, not decorative, and contributes to the rigidity of the whole leaf.

Panel

A panel fills one of the spaces created within the leaf by the stiles, rails and mullions. On a traditional timber door, solid panels are set into grooves in the surrounding members rather than being fixed rigidly, which allows the timber to expand and contract with humidity without cracking the door.

A door can have any number of panels. A simple two panel door is restrained and elegant. A six panel door has considerably more presence.

Raised And Fielded Panel

A raised and fielded panel has a central section that is thicker than the surrounding frame, projecting forward from it with a sloped or chamfered transition between the two, which is called the field. The raised centre catches the light. The fielded edges create shadow. Together they give the door depth and movement that a flat panel simply cannot match.

The fielded edge also has a practical job: it lets the panel float slightly in its grooves, moving with the timber as humidity changes through the year. Traditional joinery working with the material rather than against it.

Flush Panel

A flush panel sits level with the surrounding frame, with no projection, no recess, no shadow line. The surface of the door is even from edge to edge. Flush panels suit contemporary and minimalist design and are particularly common on internal doors, where the brief is clean and uninterrupted surfaces.

Rebate

A rebate is a stepped recess machined into the edge of a door or frame so that one surface overlaps the other when the door closes. On a pair of doors, one leaf has a rebate cut into its meeting edge so it laps over the other, eliminating the gap at the centre.

It improves the draught seal, reduces noise transmission and makes the closed pair feel considerably more solid.

Glazing And Glass

Most external timber doors include some glazing, and the type of glass matters more than many people realise. It affects how much light comes in, how much heat stays in, what level of privacy you get and how the door performs if someone tries to break it. Here are the terms worth knowing.

Light

In the context of doors, a light is an individual pane of glass within the door or its frame. A two light door has two separate glazed sections. The term is useful because it gives you precise language when discussing a glazing layout. One large central light reads very differently from four smaller lights divided by bars.

Double Glazing

A double glazed unit has two panes of glass separated by a sealed cavity, typically filled with argon gas. The cavity dramatically reduces heat loss compared to a single pane, and double glazing is now standard on virtually all external timber doors. In most new installation and replacement situations it is also a building regulations requirement.

Triple Glazing

Triple glazing adds a third pane and a second sealed cavity. The thermal and acoustic performance improves further, and it is worth considering on exposed elevations or where noise is a genuine issue.

The additional weight needs to be factored into the door design. Heavier glass means heavier hinges and a more substantial frame, which is not a problem, but worth specifying correctly from the outset.

Laminated Glass

Laminated glass bonds two or more panes together with a transparent plastic interlayer. If the glass breaks, the interlayer holds the fragments in place. The opening stays largely sealed rather than becoming immediately accessible.

It is the preferred choice where security is the priority: entrance doors, sidelights, any glazed area near floor level.

Toughened Glass

Toughened glass is heat treated to make it several times stronger than standard glass. When it does break, it shatters into small rounded pieces rather than large sharp shards, which significantly reduces injury risk.

Building regulations require it in certain positions, typically any glazed area within a set distance of the floor or a door edge. Toughened and laminated glass are often used together, toughened for strength and laminated for security.

Frosted Glass

Frosted glass diffuses light without blocking it, letting daylight through while obscuring the view. It is made by sandblasting, acid etching or applying a specialist film to the surface, with the degree of obscuration varying depending on the treatment used. Some give a light privacy, others are almost fully opaque.

It is commonly used in entrance door panels and sidelights where you want natural light but not a clear view of whoever is standing outside, or inside.

Astragal Bar

An astragal bar is a decorative strip applied to the surface of a sealed glazed unit to divide it visually into smaller panes, replicating the traditional look of individual glass lights without the thermal penalty of true structural glazing bars. On a door, astragal bars are a cost effective way to get a period appearance on a modern double glazed unit.

One caveat worth knowing: for listed buildings and conservation area applications, many planning authorities require true structural glazing bars rather than surface applied strips. It is worth confirming this before you specify.

Fanlight Glazing

The glazing in a fanlight tells you a lot about the age and character of a property. Georgian fanlights typically use fine structural glazing bars in a radiating or geometric pattern, delicate, precise and architectural. Victorian fanlights are more likely to feature etched, frosted or coloured glass with heavier, more decorative leading.

Getting the fanlight glazing right is one of the details that makes a restored or replaced entrance door feel authentic rather than approximate.

Hardware And Security

The hardware is what you interact with every day. The handle you pull, the lock you turn, the letterbox you open. It also determines how well the door performs against forced entry. These are the terms on any good hardware schedule.

Hinge

A hinge connects the door leaf to the frame and allows it to swing. On a solid external timber door, the hinges carry the full weight of the leaf through every opening and closing, which adds up to a lot of cycles over a door’s lifetime.

Ball bearing hinges use ball bearings at the pivot point to reduce friction and wear. They are the standard choice for heavy external timber doors, and the number and size specified should reflect the weight of the door rather than being selected as an afterthought.

Multi Point Lock

A multi point lock engages at several points along the frame simultaneously when the key is turned, typically at the head, the cill and one or more points along the latch jamb. Compare that to a single point lock, which holds the door at one location only.

The result is a door that is significantly more resistant to forced entry and that seals much more firmly against the frame at every locked point. On a quality external timber door, multi point locking is standard.

Mortice Lock

A mortice lock sits inside a recess cut into the edge of the door leaf, hidden within the door rather than mounted on its surface. It contains both a latch, which holds the door closed automatically as it swings shut, and a deadbolt, which needs a key or thumb turn to move.

Because the lock body is concealed within the door, it is more secure than a surface mounted lock and considerably neater.

Deadbolt

A deadbolt is the bolt within a lock that only moves when you turn a key or thumb turn, unlike a spring latch, which closes automatically. When the deadbolt is thrown, the door stays put regardless of what force is applied to it.

On a multi point lock, operating the deadbolt engages all the locking points at once. The quality and security rating of the deadbolt is the single most important factor in how well the lock actually performs.

Strike Plate

The strike plate is the metal plate in the latch jamb that the latch and deadbolt engage with when the door closes. It reinforces the frame at the point most likely to be targeted in a forced entry attempt.

The fixing method matters as much as the plate itself. Long screws that pass through the frame and into the structural wall behind it make a significant difference to how much force the installation can absorb.

Escutcheon

The escutcheon is the decorative plate around the keyhole or euro cylinder on the face of the door. It protects the timber from wear caused by daily key use and conceals the lock fixing beneath it.

On a period timber door, the escutcheon is one of those details that either pulls the entrance together or lets it down. It should be chosen to match the rest of the ironmongery, the hinges, the handle, the letterbox, in style, finish and scale.

Euro Cylinder

The euro cylinder is the cylindrical mechanism inside the lock case, operated by a key from outside and a thumb turn from inside. It is the standard format for most modern external timber doors, and importantly, it can be swapped out independently if the lock needs rekeying or upgrading.

Security ratings on euro cylinders vary considerably. The cylinder is often the weakest point in an otherwise solid lock, and it is worth specifying one that has been tested and rated accordingly.

Letterbox

The letterbox, sometimes called the letterplate, is the slot through which mail is delivered. On a timber door it should be fitted with a draught flap or brush seal to prevent heat loss and stop cold air pushing through when the post has gone.

Position, size and finish all matter. The letterbox sits in the most visible part of the door, and a well proportioned, well matched letterplate looks considerably better than an undersized one bolted on as an afterthought.

Kick Plate

A kick plate is a protective metal plate on the lower portion of the push side of the door, covering the area most likely to take impact from feet, bags, buggies and anything else that gets nudged against it in daily use. It protects the timber finish and the door face from the kind of gradual damage that is invisible in the short term but obvious after a few years.

On any door that sees regular traffic, a front door, a back door opening onto a utility room, it is a sensible addition.

Weather And Energy Performance

A door’s ability to keep out the cold, manage moisture and reduce heat loss is as important as any other part of the specification, particularly on an exposed elevation or a property with high heating costs. These are the terms that describe how a door performs against the elements.

Weatherstripping

Weatherstripping is the sealing material fitted around the edges of the door leaf to close the gap between it and the frame. It keeps out cold air, wind driven rain and noise, and is one of the primary contributors to the thermal performance of any external door.

Good weatherstripping maintains its compression and effectiveness for years. Poor weatherstripping flattens, hardens and fails well before the door itself does. It deserves as much thought in the specification as the lock or the glazing.

Insulated Core

An insulated core is a layer of rigid foam, or similar insulating material, set within the door leaf between the outer faces. It reduces the rate at which heat passes through the door and improves both thermal and acoustic performance.

A door with a well insulated core feels noticeably more solid and quiet when it closes. It is one of the details that separates a door built for performance from one built purely for appearance.

U Value

The U value of a door measures how quickly heat passes through the complete unit, frame and glazing included. The lower the number, the better the insulation. UK Building Regulations set maximum U values for external doors in new build and replacement situations.

A well specified timber door with a good insulated core and quality double glazing comfortably meets current regulations, and in some cases outperforms standard uPVC and composite alternatives, which is not the assumption most people arrive with.

Air Leakage Rating

Air leakage refers to the amount of air that passes through the joints and gaps around a closed door. Even a well fitted door will allow some movement, but too much leads to cold spots near the entrance, higher heating bills and draughty hallways that no amount of insulation elsewhere can fully compensate for.

A door’s air leakage rating is a measure of how well it limits this movement when closed. A low rating means the door seals effectively against the frame. The quality of the weatherstripping, the precision of the fit and the performance of the threshold seal all contribute to how well the door achieves this.

Solar Gain

Solar gain measures how much warmth from sunlight passes through the glazed sections of a door. Whether this is a benefit or a drawback depends on the orientation of the entrance and the room behind it.

A south facing hallway with large glazed panels can overheat on a bright day if the glazing specification does not account for solar gain. A dark north facing entrance, by contrast, might benefit from glazing that allows more warmth and light through. It is worth raising with your joiner or glazing supplier when the door faces a sunny elevation.

Condensation Resistance

Condensation resistance indicates how well the glazing and frame combination prevents moisture forming on the inside surface of the door during cold weather. Poor condensation resistance shows up as persistent misting on the glass, water running down the frame and, over time, moisture damage to the timber and floor finish around the door.

Good condensation resistance is largely a product of the glazing specification and the quality of the seals between the glass unit and the frame. A well made door with correctly specified double glazing will rarely suffer from it.

Rain Deflector

A rain deflector is a shaped profile or drip moulding fitted to the outside face of the door or frame, positioned to direct water away from the face of the door and prevent it running into the joints around the frame or threshold. On an exposed elevation, particularly one that faces the prevailing wind, a rain deflector makes a measurable difference to how much water reaches the vulnerable parts of the installation.

It is a small detail that is easy to overlook in a specification but difficult to add retrospectively once a door is fitted.

Materials And Finish

What a door is made from and how it is finished determines how it performs over its lifetime, how much maintenance it needs and whether it still looks right in ten or twenty years. These are the terms that appear on material specifications.

Timber

Timber is the natural choice for a bespoke handcrafted door. No manufactured material replicates the warmth, the grain or the character of real wood, and a well made timber door will outlast most alternatives by decades. Softwoods such as European redwood and pine are widely used for painted doors: workable, stable, excellent when properly finished. Hardwoods including oak, sapele and accoya offer greater durability for exposed locations or where a clear or stained finish is wanted.

At Turner & Co, we select premium sustainably sourced timber for each door based on the property and the client’s brief. Where possible we source our own trees directly from local woodlands.

Composite

Composite doors use a glass reinforced plastic or similar skin over a foam filled core, which gives them good dimensional stability and very low maintenance requirements. They are available in a wide range of colours and panel styles designed to mimic timber.

The trade off is finish quality over time. A manufactured skin does not age the way real timber does, cannot be refinished, and cannot be repaired in the same way. A well made bespoke timber door, properly maintained, will outlast most composite products and carry more character throughout its life.

Veneer

A veneer is a thin slice of real timber applied over a core of MDF, plywood or engineered board. It gives the appearance of solid timber at lower cost and, in some circumstances, with better dimensional stability. Veneered construction is common on internal doors.

On an external bespoke door, solid timber is generally the right choice: more durable, more authentic, and capable of being repaired and refinished repeatedly over its lifetime.

FSC Certified Timber

FSC certification confirms that the timber in a door has been sourced from forests meeting the standards of the Forest Stewardship Council, an independent organisation that sets internationally recognised guidelines for responsible forestry, covering environmental protection, biodiversity and the rights of local communities.

At Turner & Co, all of our timber is sustainably sourced. Wherever possible we source our own trees directly from local woodlands and farms, which means we know exactly where the material comes from before a single joint is cut.

Micro Porous Paint

Micro porous paint allows moisture vapour to move through the painted surface while blocking liquid water. Timber expands and contracts as humidity changes. A finish that cannot breathe traps that moisture inside the wood, and the result is blistering, peeling and eventually rot.

A properly applied micro porous system, sealed on all faces of the door including the top and bottom edges, dramatically extends the life of a timber door. Most premature paint failures on timber doors come back to edges and faces that were left unsealed at the time of fitting.

Spray Finish

A spray finish is a paint or lacquer applied using spray equipment rather than a brush or roller. The result is a smooth, even surface with no brush marks or texture variation, noticeably closer to a factory finish than anything achievable by hand on site. The choice of colour and finish is agreed at the design stage and applied before the door leaves the workshop.

At Turner & Co, all of our doors are spray finished in our Ipswich workshop before installation. The door arrives on your property ready to go, with a high quality coat that has been applied under controlled conditions rather than in whatever the weather is doing on the day.

Moulding

Moulding is the shaped profile worked into or applied to the surfaces and edges of a door. It is the detail that frames the panels, softens the transitions and gives the door its period character. The profile matters: an ovolo reads differently from an ogee, which reads differently from a chamfer or a bolection.

On a well crafted bespoke door, the moulding is cut directly into the timber. On a mass produced door, it is applied separately, and the difference is visible if you know what you are looking at.

Ovolo Moulding

The ovolo is a convex curved profile worked into the edges of the rails, stiles and panel margins on a traditional timber door. It creates a rounded shadow line between the flat door face and the panel beside it, giving Georgian and Victorian doors their characteristic depth and light.

The quality of the ovolo across a door is one of the clearest indicators of the standard of the joinery. Consistent, crisply cut profiles throughout suggest a joiner who pays attention to the detail. Variation and flatness in the curve suggest the opposite. At Turner & Co, ovolo moulding is used across our traditional and heritage door range wherever the design calls for authentic period character.

What To Do With All Of This

A door specification is not a test. You do not need to memorise the difference between a frieze rail and a middle rail before you call a joiner. What matters is that when a quote lands on your doorstep describing a six panel raised and fielded door with ovolo moulding, multi point locking, toughened double glazed lights and a micro porous spray finish, you can read it and understand what you are actually getting.

The same goes for a conversation with a planning officer about a listed building or conservation area application. Knowing that an astragal bar is a surface applied strip rather than a true structural glazing bar, or that a Georgian fanlight should use a radiating pattern rather than plain glass, is the difference between knowing what to ask for and hoping someone else gets it right.

Keep this guide somewhere you can come back to. Whether you are looking up door parts before a call with your joiner, checking a term on a quote or preparing for a planning conversation, having the right word at the right moment makes everything considerably easier.

Bespoke Timber Doors From Turner & Co

At Turner & Co Bespoke Joinery Ltd, all of our doors are handcrafted in our Ipswich workshop using premium sustainably sourced timber. As a family run business with a deep background in traditional timber joinery, we design and build every door to the specific requirements of the property: a bespoke front door for a Georgian townhouse, French doors opening onto a garden, a stable door for a country cottage, bi fold doors for a contemporary extension.

If you are planning new doors and want to discuss our services, call us on 07952 907 946 or email harry@turnerandco.co.uk.

Frequently Asked Questions