Stairbuilders and Manufacturers Association Glossary.

The SMAs Glossary has been updated and is available fully below or in a viewable and downloadable PDF document.

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 Glossary of Stair Terminology.



Adjacent A term used to describe two surfaces which are directly next to or touching each other (Architectural Woodwork Institute, AWI®)

Aesthetic The appearance and feel of those surfaces that will be exposed or semi-exposed following installation (Architectural Woodwork Institute, AWI®)

Angled StairwayA stairway of successive flights that are at an angle other than 180º to each other with a landing between them

Apron – A horizontal trim member that extends vertically below a horizontal surface to support the projected edge of a table or countertop typically at an open area or to support a window stool or landing nosing, See FASCIA


Balanced Steps (Dancing Steps) – Winders that do not radiate from a common center but are distributed uniformly through equal segments of the walk line

Balcony – An elevated level area of floor or landing with a balustrade visible from below

Baluster  A vertical member used as in-fill to limit the size of openings within a balustrade and/or provide support to the top of a balustrade or guard system by transferring a portion of the load applied to the balustrade to the structure of a stair or floor system

Baluster, Pin Top A baluster with a round top that is fitted into holes drilled in the bottom of the rail

Baluster, Square Top – A baluster with a square top end

Balusters, Raked – Two or more balusters on a step with details in profile that are oriented to follow the rake or inclination of the stair

Balusters, Stepped – Two or more balusters on a step with details in profile that are oriented parallel in height to the horizontal surface of the tread

Baluster, Twist (Twist, Newel) – 1. A square metal baluster (newel) that is twisted to give the appearance of a spiral along its axis of length, 2. A baluster (newel) with a convex bead that twists in a spiral along its axis of length to appear as a rope, 3. A baluster (newel) with a concave flute that twists in a spiral along its axis of length

Balustrade  A system of rails, newels, balusters, panels, screen or other ornamental components used to separate two areas. Balustrades used to minimize falls from elevated walking surfaces and the sides of stairs are also guards

Banister – 1. A simple post-to-post balustrade typically with small diameter, square or rectangular section balusters used to provide a handrail and minimize falls from the side of stairs, 2. A corruption of the terms baluster/balustrade

Block – The solid piece of wood or face laminated pieces/blocks of wood from which sections of curved rail or other curved stair or balustrade components are cut or shaped

Blocking Wood blocks or other elements attached to the building structure to provide for the transfer of loads and/or the secure fastening of objects at points between structural elements such as studs or joists where voids in the structure do not permit direct fastening to the structure

Bracket – 1. A triangular structural support element used to transfer loads from one element to another by changing the direction of the applied load, 2. A support used to attach a handrail to a wall, 3. An element connecting the tread and riser usually applied to the face stringer as a decoration, 4. An element attached to a stringer to support a tread

Bullnose – 1. A half circular shape applied to or machined on the edge of a component, 2. A type of starting step with half circular end(s) in plan view projecting beyond the width of the stairs above

Buttress (Curb) – A closed stringer system on the open side of a stair built up in thickness, sometimes with a core wall or blocking, with a finished opposing exposed side, and a cap to receive the balusters


Cable (Wire Rope) – A rope of wire or fiber used in cable railing systems usually made of stainless steel or galvanized material

Cable Railing – A guard or balustrade with cable in-fill

Cap – 1.  A moulded object or board used to finish the top of an object such as a wall, or closed stringer, 2. That part of a rail fitting that is attached to the top end of a newel or newel cap, 3. The applied top of a box newel, 4.  A false end tread

Cap, Newel – See CAP and also see OPENING, QUARTER TURN, TANDEM below

Cap, Opening – 1. A horizontal rail fitting at the start of a level balustrade system at the top of a newel, See CAP, 2. A horizontal rail fitting used as a component of a starting easement at the top of a starting newel

Cap, Quarter Turn – A horizontal rail fitting used to connect two rails at an angle of 90-degrees at the top of a newel

Cap, Tandem – A horizontal rail fitting used to connect two rails at an angle of 180-degrees at the top of a newel

Carriage A system of rough stringers attached to the building structure providing for the support and or attachment of the treads, risers and face stringers of a stair and often the ceiling or soffit below

Cathedral (Grain) – A series of stacked and inverted “U” or “V” shaped patterns, most noticeable in species which exhibit a high amount of contrast between springwood and summerwood, common in plain sawn/sliced

Channel Glazing – A method of glazing which uses a ‘U’ shaped channel to hold glass panels in place

Closed – Typically referring to condition of enclosure such as walls at the side of a stair or that portion of the side of a step that is enclosed by a stringer extending above the treads

Compatible Consistent or similar in appearance to other components within an architectural woodwork assembly, See COMPATIBLE FOR COLOR AND GRAIN, COMPATIBLE FOR COLOR, COMPATIBLE SPECIES (Architectural Woodwork Institute, AWI®)

Compatible for Color Used to describe a material which is of similar color, hue, and tone to the adjacent components. Though color compatible does not imply an exact match, the differentiations between color compatible materials are inconspicuous (Architectural Woodwork Institute, AWI®)

             Compatible for Color and Grain Members shall be selected so that:

– Lighter-than-average color members will not be adjacent to darker-than-average color members and there will be no sharp contrast in color between the adjacent members, and

– The grain of adjacent members shall not vary widely or be dissimilar in grain, character, and figure (Architectural Woodwork Institute, AWI®)

Compatible Species Different species which are able to exist in a harmonious combination of color and grain (Architectural Woodwork Institute, AWI®)

Component An individual piece of solid stock or plywood that forms an item of woodwork (Architectural Woodwork Institute, AWI®)

Concealed Surfaces Surfaces that are neither visible nor accessible to the building occupants and/or general public under normal circumstances (Architectural Woodwork Institute, AWI®)

Conspicuous Detectable; readily visible with the naked eye when observed under normal lighting conditions. May have further restrictions involving distance related to aesthetic grade levels defined in the Architectural Woodworking Institute Standards (Architectural Woodwork Institute, AWI®)

Contract Document The contract documents consist of the conditions of the contract (general, supplementary, and other conditions), drawings, specifications, addenda, other documents issued after execution of the agreement, all of which form the contract. The contract represents the entire and integrated agreement between the parties hereto and supersedes prior negotiations, representations or agreements, either written or oral (Architectural Woodwork Institute, AWI®)


Cove – A supporting moulding profile with a concave quarter round radius or arc on the face, See SCOTIA

Crown, End Grain The arching of growth rings viewed from the end of solid lumber. When gluing multiple boards, crown direction is alternated

Crown, Face Grain The peak of the arching pattern viewed on the face of natural or manufactured products, See CATHEDRAL

Curb – A shoe rail mounted directly on the floor or blocking attached to the floor with a cap to provide for the termination of the balusters above the adjoining walking surface

Curtail Step – See VOLUTE STEP



Easing – 1. An arc that is tangent to two straight intersecting lines providing a smooth rounding instead of an angular intersection, 2. An easement in a rail or stringer, i.e., up easing, over easing, 3. Sanding or shaping a radius on the corner of a board to yield an “eased edge

Easement – A rail fitting that provides a vertically curved easing between two intersecting rails or a rail and cap as in a starting easement

Edge Any surface of a board or panel other than its face and back

Edge Glued Boards or staves glued together at the edges to increase width, typically glued with alternating end grain crown

Expansion Joint A space or joint between two members of a fabrication, installation, or product that permits movement between two members due to shrinking and swelling without incurring structural damage (Architectural Woodwork Institute, AWI®)


False End Tread or Riser (False End Caps) – Decorative elements resembling the end of a tread or riser applied to the surface at the end of a structural sub-tread or riser with the remaining exposed sub-tread/riser to have a floor covering applied such as carpet

Face – 1. The higher grade side of any panel in which the outer plies are of different veneer grades, 2. Either side of a panel in which there is no difference in veneer grade of the outer plies, 3. The side of a component to be exposed or visible in the finished product

Face Mould – A template used in handrailing to describe the curved sides and ends of a wreath on the block to be carved

Fascia – 1. A board or panel applied as a vertical or near vertical surface, at or near the ceiling, 2. At stairs, a component applied as the vertical surface below a landing nosing, often with a moulding

Ferrule – A sleeve or ring that is compressed or swaged onto cable

Fillet – A thin strip or moulding that fills the exposed plow or groove between balusters in a rail, bottom rail, shoe rail, sub-rail or cap

Finial – An ornamental element used at the top end of a newel post

Fitting, Rail – A component or combination of components that are profiled to match rail patterns and used to connect rails in a continuous fashion at horizontal changes in direction, vertical transitions, or for ornamentation

Fitting, Quarter Turn A rail fitting that turns 90 degrees, See LEVEL QUARTER TURN and CAP, QUARTER TURN

Flier (Flyer) – A rectangular tread

Flight – An uninterrupted series of fliers or winders or any combination thereof from one landing to the next

Flitch – One log sliced into veneer leaves, kept in order, separated into bundles (Architectural Woodwork Institute, AWI®)

Floor to Floor Height – See RISE, TOTAL

Flute One of a series of parallel grooves referred to as fluting used as decorative details in vertical surfaces of such elements as columns, mouldings, balusters, newels, or furniture legs


Gait Line – A line that follows the angle of the stair connecting the nosings of the treads also called nosing line

Gasket – A seal that fills the space between 2 or more adjoining surfaces, generally to prevent leakage from or into joined objects

General Contractor – A general contractor, responsible for executing the contract for a building project and coordinating the work between the subcontractors as well as the chain of communications between the owner, design professionals, and subcontractors (Architectural Woodwork Institute, AWI®)

Glass, Annealed – A process designed to eliminate or limit the internal stresses of the cooling of glass. Under normal conditions, the surface of glass will cool more rapidly than the center causing internal stresses which may cause the glass sheet to crack, shatter, or even explode. By submitting the glass to controlled cooling in a special oven known as a “lehr”, the glass is allowed to cool to a temperature known as the “annealing point”. When the glass reaches this point, the temperature is stabilized for a specific length of time, to allow stresses in the glass to relax

Glass, Decorative – Glass that is frosted, colored, textured, or stained

Glass, Float – A process for the production of high-quality sheet glass whereby a ribbon of molten glass is fed across a bath of heated liquid, usually molten tin, in a carefully controlled atmosphere. This method gives the sheet uniform thickness and very flat surfaces

Glass, Laminated (Compound) – Consists of 2 or more sheets of glass with one or more viscous plastic layers between the glass panes. When this glass breaks, the pieces remain attached to the internal plastic layer and the glass remains transparent

Glass, Low Iron – The amount of iron is reduced to make the glass more transparent with edges that are clear or light blue

Glass, Tempered (Toughened) – A type of glass processed by controlled thermal or chemical treatments to increase its strength compared to normal glass. Tempering puts the outer surface into compression and the interior into tension. This treatment causes the glass, when broken, to crumble into small granular chunks instead of splintering into jagged shards

Glass Clamps Used to connect glass panels to a post, structure or inline to another panel

Glass Edge Treatments

Bevel: Glass that has its edges cut to a specific angle and size in order to produce a specific elegant look. A bevel edge can range in size depending on the angle of the bevel and thickness of the glass

Polish: Glass that’s edges are ground smooth, finished with a shiny or gloss polish resulting in a sleek appearance

Profiled:  A glass edge having a more complex radius or multi angled shaped. This edging is more decorative that a simple beveled edge, e.g., ogee profile

Glass Panel (Pane or Sheet) – A flat or curved piece of glass

Glazing Compound – Used in wet glazing/anchoring methods of bedding, and setting the edges of glass panels in a frame and often to provide a seal between the exterior and interior sides

Glue Blocks – Blocks of wood attached to the underside of a stair at the joints between the risers, treads, and stringers to strengthen the joint and minimize movement that causes squeaks

Going – The horizontal distance between two successive nosings on a stair, See RUN (UNIT RUN) or TREAD DEPTH

Gooseneck – A combination of easing(s), rail segments and/or caps that provide for the continuous transition of a rake rail to a level rail at the top of a flight or from rake rail through a level turn to a rake rail at a turn in the stairway

Grain, End – The grain as seen on a cut made at a right angle to the direction of the fibers (grain), such as on a cross section of a tree, typically the surface at the end of a length of lumber (Architectural Woodwork Institute, AWI®)

Groove – A partial depth cut with two opposing sides, when machined in grained material the cut is parallel with the grain (Architectural Woodwork Institute, AWI®)

Guard – A component or system of components such as rails, newels, balusters, panels or other ornamentals used to minimize falls from elevated walking surfaces and the sides of stairs


Hand (Stairs) – 1. The direction a stair or handrail turns in ascent, left or right, 2. The side of the stair as viewed in ascent, left or right, 3. The identification of a component for its intended use as referenced by the side of the stair in ascent, e.g. right hand returned tread to be used on a right hand open stair

Handrail – A sloped or horizontal rail intended for grasping by the hand as an assist for guidance, support, pulling, or arresting a fall

Handrailing – The craft of designing and constructing wreathed handrails for geometrical stairs

Hanger Bolt – A bolt that has course lag thread on one end instead of a head with finer machine thread on the opposite end to accept a nut

Header 1. A floor-framing member at the edge of a floor opening that “heads off” the floor joists running up to a well opening, 2. The joist(s) at the edge of a floor opening, 3. The joists at the edge of a landing supporting the end of a flight

Headroom  1. The clear vertical space allowed for the user of a stairway to prevent striking their head, 2. The vertical distance from the plane of the nosings of a flight, extended to the floor beyond the first riser, to any obstruction above the walking surface of the stair generally a minimum of 80 inches throughout the stairway including the landings

Horse – 1. The triangular point or “sawtooth” portion of a cut string or carriage to which the tread and riser are attached, 2. A rough string


Inconspicuous Not readily visible without careful inspection at a distance of 610 mm [24”] for PREMIUM GRADE, 1219 mm [48”] for CUSTOM GRADE, and 1829 mm [72”] for ECONOMY GRADE (Architectural Woodwork Institute, AWI®)

Infill – A term used in the ICC structural requirements to describe that portion of a guard system below the top rail

Installer A person or organization that regularly engages in the practice of installing architectural woodwork (Architectural Woodwork Institute, AWI®) 

Intermediate Rail – 1. A horizontal component that connects two stiles between the top and bottom rails, 2. A horizontal or sloped component of a balustrade that is located between the top rail and the bottom of the balustrade




Kerfing – A wood bending technique using a series of uniform, shallow cross cuts on the back of a board that do not penetrate the face allowing the back surface to compress to a smaller radius increasing the flexibility without reducing the thickness

Kite – A winder in a 90-degree corner that is shaped like a kite in plan view

Knee Wall – 1. A spandrel wall that extends above the gait line to form the core of a buttress or curb at the open side of a stair, 2. The spandrel wall supporting an open string

Knuckle – Decorative metal element(s) into which a metal baluster is inserted or band(s) that encircles the baluster used as an ornament in the middle portion of a baluster


Lamb’s Tongue – An ornamental cyma curved rail termination often with carved details

Landing – 1. The walking surface at the top and bottom of a flight at a floor level to provide clear approach to the stair or to the floor level from the stair, 2. An intermediate level platform between flights used to change direction of the stair and/or provide a resting place typically with dimensions approximating the width of the flights served

Landing, Half Space – An intermediate landing at a stairway turn of 180 degrees

Landing, Quarter Space – An intermediate landing at a stairway turn of 90 degrees

Landing Nosing – A moulding used to finish the floor or landing edge at a level balustrade

Landing Tread –  1. The top tread in a flight supported by the top riser that is attached in alignment with the floor-surface with the same nosing projection as the treads in the flight below, 2. The moulding used as landing tread and landing nosing

Landing Tread, Bending – Thin, flexible, longitudinal-sections of a landing tread profile that are moulded individually such that bending and laminating the sections together will provide a curved landing tread of the composite profile

Lamination – A process to produce a product by assembling multiple layers or plys of materials using heat, pressure, welding, or gluing

Level Quarter Turn A rail fitting that turns 90 degrees in the level or horizontal plane

Leaf An individual piece of wood veneer from a bundle, flitch, or boule (Architectural Woodwork Institute, AWI®)

Lumber Pieces of wood thicker than 6.4 mm [.252”] no further manufactured than by sawing, planing, crosscutting to length, and perhaps edge machining (Architectural Woodwork Institute, AWI®)


Manufacturer A person or organization that regularly engages in the practice of manufacturing, prefinishing, and/or installing architectural woodwork (Architectural Woodwork Institute, AWI®)

Manufacturer/Supplier Producer or supplier of architectural woodwork components (Architectural Woodwork Institute, AWI®) 

Mechanical Fastener The generic term for securing devices that are used in the fabrication and/or installation of architectural woodwork such as dowels, dowel screws, splines, biscuit splines, nails, screws, bolts, pins, etc. (Architectural Woodwork Institute, AWI®)

Metamerism – An apparent change in wood color caused by human perception when cells are exposed to differing angles of light a phenomenon causing an apparent change in color caused by varying lighting conditions (Architectural Woodwork Institute, AWI®) 

Mineral Streak An olive to greenish-black or brown discoloration of undetermined cause in hardwoods. (Architectural Woodwork Institute, AWI®) 

Miter Joint The joining of two members at an angle that bisects the angle of junction (Architectural Woodwork Institute, AWI®) 

Miter, Lock Joint A miter joint employing a tongue and groove to further strengthen it (Architectural Woodwork Institute, AWI®) 

Miter, Shoulder Joint Any type of miter joint that presents a shoulder, such as a lock miter or a splined miter (Architectural Woodwork Institute, AWI®) 

Modulus of Elasticity (MOE) A measure of stiffness; a physical parameter that reflects the mechanical behavior of any material in response to induced stress due to loading

Modulus of Rupture (MOR) – The maximum load-carrying capacity of a member under bending load. Modulus of rupture is an accepted criterion of strength (Architectural Woodwork Institute, AWI®) 

Moisture Content – The weight of water in wood expressed as a percentage of the moisture free wood’s weight

Moulding* – A decorative strip of material, usually having a curved or profiled face or edge, though it may also be square. Some common mouldings used are listed below   *Spelled differently from “mold” – a multicellular fungus.

Moulding Profile (Rail Profile) The shape as described by a section perpendicular to the length of the moulding (Architectural Woodwork Institute, AWI®)

Moulding, Base Cap A moulding applied to the top edge of a base moulding to add aesthetic affect or increase height (Architectural Woodwork Institute, AWI®)

Moulding, Base or Baseboard Mouldings used to trim the intersection of a wall or cabinet and the floor (Architectural Woodwork Institute, AWI®) 

Moulding, Base Shoe 1. A moulding, used at the joint between base and floor and where the starting riser meets the floor, 2. A base made of wood or aluminum, sometimes recessed in the floor, used to secure the bottom of a glass panel (Architectural Woodwork Institute, AWI®) 

Moulding, Bead Moulding A narrow, half-round moulding that is continuous or divided into bead-like segments (Architectural Woodwork Institute, AWI®) 

Moulding, Cove A supporting moulding profile with a concave quarter round radius or arc on the face, See SCOTIA (Architectural Woodwork Institute, AWI®) 

Moulding, Handrail A sloped or horizontal rail intended for grasping by the hand as an assist for; guidance, support, pulling, or arresting a fall (Architectural Woodwork Institute, AWI®)


Newel (Newel Post) – 1. A vertical element or post used to connect balustrade components to the structure of a stair or floor system, 2. A vertical post to which carriages, stringers and balustrades can be attached at junctions and angular turns in the stairway to provide the main support for the stairs and balustrades

Newel, Box A newel, usually square in section, often made as a “box” with a hollow center, from boards joined at the corners

Newel, Half – A newel cut in half longitudinally used against a wall to provide for the termination of a balustrade

Newel, Intermediate LandingA newel located at a landing or platform between flights in a stairway or at a turn of winders

Newel, Landing A newel located at a landing or balcony

Newel, Pin Top An over-the-post newel that has a dowel pin turned on the top to fit into a hole in the bottom of a newel cap

Newel, Rake – A newel tapered at the top to attach to the bottom of a rail for additional support in the middle of a longer rake rail

Newel, Starting The first newel used at the bottom or beginning of a stairway

Newel, Twist – See BALUSTER, TWIST

Newel Bolt – A long, large, diameter hanger bolt used to top mount a newel to the floor system

Newel Drop – An ornamental element used at the bottom end of a newel

Newel Plate – A metal plate, drilled to accept fasteners near the center for attachment to the bottom of a newel, and also drilled at the perimeter for top mounting a newel to the floor, typically the exposed fasteners are concealed by carpet or wood moulding

Nominal – The stated dimension by which a product is known and sold in the market, differs from the actual dimension and is subject to variation

Nosing – 1. The leading edge of a tread or landing, 2. A rounded convex edge

Nosing Line – See GAIT LINE

Nosing Projection or Overhang – The horizontal distance measured from the leading edge of the tread to the trailing edge of the tread below.


Open – A stair that is absent of an enclosing wall and the components thereof, or the absence of a component such as the riser in an open riser stair

Open Riser Stair – A stair without risers such that the space between the treads is open

Over Easing Typically used to describe an easing in a rail with the center of its arc below the top of the rail

Over-the-Post A balustrade system that uses fittings to provide a continuous handrail over the top of the newel posts


Performance Based Refers to the lack of dictated or specifically required technical processes in lieu of a concept that allows innovation as long as the required outcomes are achieved

Picket – The vertical element in a fence, See BALUSTERS

Pitch – 1. An accumulation of resin that occurs in separations in the wood or in the wood cells themselves, 2. The slope or angle of a stair in reference to the horizontal plane, See RAKE

Pitch BlockA block of wood cut to a right triangle with the rise and run dimensions of a stair and used as an angle gauge in stairbuilding and handrailing

Plank – 1. A board, usually between 38.1 to 88.9 mm [1.500” to 3.500”] thick and 152 mm [6”] or more wide, laid with its wide dimension horizontal and used as a bearing surface, 2. In veneer matching, the assembly of dissimilar (in color, grain or width) leaves of the same species to resemble an edge glued panel made from lumber (Architectural Woodwork Institute, AWI®) 

Plate – The bottom, flat part of a rail assembly attached directly to the floor or top of a knee wall, buttress or curb typically into which the balusters or other infill terminates, See CAP and RAIL, SHOE

Platform – 1. An intermediate landing in a stairway, 2. The extension of the floor landing, which is often used as the top, tread of a spiral stairway

Plinth – The base of a baluster or newel

Plow (Plough) A rectangular groove or slot with three surfaces, cut parallel to the grain of a wood member, See GROOVE

Plowed rail  A rail, which has had the bottom, grooved or plowed to accommodate insertion of a square baluster and fillet

Plug, Button – A machined piece of wood used to conceal a counterbored hole with a truncated dome of end grain that projects above the surrounding surface

Plug, Flush – A machined piece of wood used to conceal a counterbored hole, installed to be flush

Plumb – Vertical, perpendicular to level

Ply One individual layer of veneer or core material which can be adhered together to form a panel. Grain direction may be altered between layers

Post  See NEWEL

Post-to-Post A balustrade system with rails that are interrupted by intersections with the side of the newels

Preassembled Stairs Stair components that are assembled in a controlled environment for jobsite installation as modular components of a stairway

Profile A shape cut into the face, edge or end of a component. Profiles can be illustrated by a section view perpendicular to the shape (Architectural Woodwork Institute, AWI®)



Rail – 1. A horizontal component of a stile and rail door assembly or face frame. Also refers to the horizontal components of the core assembly of a wood flush door or panel, 2. A horizontal component of a balustrade also referred to as railing in a balustrade

Rail, Bending Longitudinal sections of a profile that are moulded individually such that bending and laminating the sections together will provide a profiled curved rail

Rail, Blocked – A curved rail that is cut and shaped from blocks or segments that are joined end to end

Rail, Bottom – See RAIL, SHOE

Rail, Level A horizontal balustrade assembly

Rail, Rake A sloped rail or balustrade assembly

Rail, Shoe 1. A rail that is used to receive the bottom end of balusters when they are not connected directly to the treads, 2. A cap on the top of a closed stringer, buttress or curb that is plowed to receive the bottom square end of balusters

Rail, Sub – The lower portion of a rail member that is an aggregate of more than one horizontal element, often ploughed on the bottom to receive square top balusters and fillet

Rail, Toe – See RAIL, SHOE

Rail Bolt A hanger bolt used to join rail ends to fittings, newels or walls

Rail Fitting See FITTING, RAIL

Rail Profile (Moulding Profile) – The shape as described by a section perpendicular to the length of a rail or moulding

Rail System – See BALUSTRADE

Rake – 1. Used to describe the particular angle of an object i.e., the slope or pitch of a stair 2. Used to describe an object as being inclined i.e., rake rail

Reeding A series of parallel beads used as decorative detail in vertical surfaces of such elements as balusters or newels

Returned End – 1. The end of a moulding profile that has been mitered to extend the profile across the end and conceal the end grain, 2. The end of a handrail that is returned to a wall, post or floor to eliminate an open end that might catch the clothing of users or the objects they carry, 3. A handrail fitting with the moulding profile shaped on the end grain and used as a termination on the open end of a rail

Return – Continuation in a different direction of moulding or projections, usually at right angles (Architectural Woodwork Institute, AWI®)

Return Nosing See TREAD RETURN

Rise (Unit Rise) – The vertical distance between the leading edges of adjacent treads. Referred to in building codes as riser height

Rise, Total The vertical distance of a stairway from finish-floor to finish-floor

Riser – The vertical component of a step in the space between the treads

Riser, Bowed – A riser that is curved in plan view

Riser, Mitered – A riser crosscut on the end at an angle to the face to join the complimentary vertical riser cut of a mitered cut string

Riser, Open – Absence of a riser such that the space between adjacent treads or landings is open

Riser, Starting – See STARTING STEP

Rosette 1. A decorative and anchoring wall plate used at the termination of a rail into a wall, 2. A decorative component used at the intersection of window casing and casing at the top of a door

Run (Unit Run) The horizontal distance between two successive nosings on a stair,  from the top nosing of the flight to the bottom nosing of the flight, See GOING and TREAD DEPTH

Run, Total – The total horizontal distance of a flight of stairs


Scotia – A cove moulding with elliptical concavity

Scroll – The terminal end of a volute

Scroll Step – A type of starting step, See VOLUTE STEP

Setting Blocks – Cushions used between the edges of glass panes or panel and the frames to allow for expansion and prevent the glass from cracking

Shoe, Base and Rake – Base shoe is a decorative element used to conceal the termination of the baluster at level/horizontal surfaces, rake shoe is a decorative element used to conceal the termination of the baluster at raked/sloped surfaces

Shoe Moulding – 1. A moulding, used at the joint between base and floor and where the starting riser meets the floor, 2. A base made of wood or aluminum, sometimes recessed in the floor, used to secure the bottom of a glass panel

Shop Drawings Drawings prepared by the manufacturer/supplier or installer, serving as the primary visual communication submitted for review, comment and approval. Shop drawings may include illustrations, diagrams, schedules, material selections, product data, samples, methods of construction, joinery and attachment, finishes, and technical suggestions (Architectural Woodwork Institute, AWI®)

Skirt Board – A non-structural component used to trim the sides of stairs to which the treads and risers are fitted

Soffit – The visible ceiling attached to the bottom of a stair between the opposite stringers and/or opposing wall(s)

Spandrel – The triangular element in a staircase between the stringer and the baseboard, 2) The triangular space between the side of an arch, the horizontal drawn from the level of its apex and the vertical of its springing (See Dictionary of Architecture and Landscape Architecture by John Fleming, Hugh Honour, and Nikolaus Pevsner)

Sphere Rule Refers to the building code that limits openings in guards to the size of a certain sphere that shall not pass through the guard

Spindles  Symmetrical turnings often used in chair backs and spreaders between chair legs, See BALUSTERS

Stair – 1. A step or change in elevation of one riser height. 2. A change of elevation consisting of one or more risers. (International Code Council, ICC®) **

Stairs1. A series of steps.  2. A change of elevation consisting of one or more risers. (International Code Council, ICC®)**

**The International Code Council, ICC® requires both singular and plural forms to have the same meaning

Stair, Box 1. Stairs with closed stringers on each side that “box in” the treads and risers, 2. A prefabricated straight flight of stairs with closed stringers.

Stair, Circular – A curved stairway that is circular in plan view

Stair, Curved – A stair with some portion having an arc in plan view that is a radius, a combination of radii or an ellipse

Stair, Dextral – A stair that turns to the right during ascent

Stair, Dogleg – A stair with two flights separated by a half landing, and having no stairwell, (in elevation the angles of the flights form a dogleg shape)

Stair, Freestanding (Floating) – A stair that is unsupported by walls and attached only to the floor systems at the top and bottom of the stair

Stair, Geometrical – A stair of complex geometry in which the strings and rails are continuous from start to end with curved and straight segments of the stairway connected by wreaths, typically without newels, except the starting newel

Stair, Helical – A stair that ascends with identical winders within the space that can be defined between two cylinders of concentric circular plans, See SPIRAL STAIR

Stair, Open – A stair that is open on one or both sides that has no wall separating the stair from the adjoining space

Stair, Open Well – A stair having a stairwell

Stair, Partial Open A stair that has an open side that becomes closed by a wall part way up the flight

Stair, Scissor – Two interlocking stairways providing two separate paths of egress located within one stairwell enclosure

Stair, Sinistral – A stair that turns to the left in ascent

Stair, Slant Riser (Z Stair*) – A stair in which the risers are slanted under the tread above to minimize catching the toe of footwear at the nosing projection and/or provide for application of a runner in one continuous integral section  *The slanted/sloped riser and horizontal tread results in a ‘Z’ profile.  

Stair, Spiral* – A stairway having a closed circular form in plan view with uniform winders radiating from a minimum-diameter circle with or without a center supporting newel or column,** See HELICAL STAIR

 *A geometric spiral diminishes to a point. The term is used here to describe the common visual perspective of the stairway not the geometric form.

 ** Spiral Stairs have different definitions in the International Building Code, IBC® and the International Residential Code, IRC®.  The IBC® requires a minimum diameter supporting column to which the treads are attached.

Stair Gradient – The ratio between the rise and run of a stair used to relate the steepness in use, typically considered to be between 20 and 42-degrees when expressed as angle. Differing from ladders, which are steeper, and ramps, which are less steep

Stairbuilder – A person with skills specific to the craft of designing and constructing stairways and balustrades

Staircase – That part of the building set apart for the stairs and balustrade generally including the well opening and adjacent walls

Stairway One or more flights of stairs, with the necessary landings and platforms connecting them, to form a continuous and uninterrupted passage from one level to another. (International Code Council, ICC®)

Stairway, ‘L’- Shaped – A stairway with two flights joined by a quarter space landing that is shaped in plan view like the letter ‘L’

Stairway, ‘U’ – Shaped – A stairway with flights joined by one or more landings that is shaped in plan view like the letter ‘U’

Stairwell  The inner clear opening formed by; turning flights within a well opening or between a flight and the edge of the well opening

Stairwork Work specific to the craft of designing and constructing stairways and balustrades

Standoff – A component or part to an assembly that functions to offset one part of the assembly from another

Starting Easing A rail fitting comprised of an up easing and opening cap used at the bottom of a stairway attached to a starting newel

Starting Fitting – A rail fitting comprised of an up easing or wreath with a cap, turnout, or volute/scroll used at the bottom or beginning of a stair attached to a starting newel

Starting Step 1. The first tread and riser at the bottom of the stair, 2. A tread with curved end that is used at the start of the stairway at the bottom

Starting Step, Bullnose – A tread with half round end(s) in plan view projecting beyond the face string of the stair

Starting Step, Quarter Turn – A starting step that has quarter circle rounded end(s) at the leading edge

Stave – One of several boards edge glued to form a wider board or panel (Architectural Woodwork Institute, AWI®)

Stave Core A core constructed of glued wood blocks (Architectural Woodwork Institute, AWI®)

Step  1. A change in elevation of one riser height to a floor or landing without a tread, 2. A unit segment of a stair, consisting of a riser and the tread above

Stile and Rail Construction A woodworking technique often used in the making of doors, wainscot, wall surfacing, underside of stairs, ceilings, and other decorative features for cabinets and furniture; generally consists of a center surface or panel such as wood, glass, or drywall two vertical members known as stiles, and two horizontal members known as rails. When assembled, the members create a framed panel (Architectural Woodwork Institute, AWI®)

Stringer (String) The supporting inclined elements to which the treads are attached that serve to transfer both live and dead loads of the stair to the building structure

Stringer, Closed – A stringer that encloses the ends of the treads and risers typically with the top edge following the angle of the stair above the line of the nosings

Stringer, Curb A closed stringer system on the open side of a stair built up in thickness, sometimes with a core wall or blocking, with a finished opposing exposed side, and a cap to receive the balusters, See BUTTRESS

Stringer, Cut – A stringer that is cut or notched on the upper edge for support and attachment of the treads

Stringer, Face – The exposed stringer on the open side of stairs. Called a skirt board or fascia when not supporting the treads and risers

Stringer, Housed – A closed stringer that “houses” the ends of the treads and risers projecting into routed recesses in the stringer

Stringer, Mitered Cut – A cut stringer with the riser cuts mitered to join a riser with a complimentary miter on the end to be joined

Stringer, Mortised – A closed stringer that has been machined so that the ends of the treads and risers project into routed recesses

Stringer, Open – A face stringer that is cut or notched on the upper edge for support and attachment of the treads such that the profile of the steps can be seen from the side

Stringer, Rough – A cut stringer to which the treads and risers are attached that is concealed and attached to the structure typically in the rough framing phase

Stringer, Routed – See STRINGER, MORTISED

Stringer, Wall – A stringer that is applied to the wall on the closed side of a stair

Stringer Margin (Stringer Reveal) – 1. The distance from the gait line to the top edge of a closed stringer,  2.  The width from the bottom of a cut string to the depth of the cut notch

Structural Composite Lumber (SCP) A man-made composite that utilizes stranded wood fibers from a variety of tree species, providing an alternative to dimension lumber. The material is engineered for strength and stability. While not really “lumber”, it is marketed as a lumber substitute to be used in place of stave lumber core materials (Architectural Woodwork Institute, AWI®)

Sub-Tread – A concealed rough tread used to support the visible finish tread

Suction Cups – A tool with vacuum actuated cups with heavy duty handles that allows for convenient grasp, maneuver, and release of heavy glass panels

Swage – 1. To compress or crimp a ferrule to cable, 2. A tool used for swaging

Swaging Stud A stud with attached ferrule to swag on the end of a cable.  The end may be threaded to attach to a terminal or turnbuckle

Swaging Tool – A tool used for swaging (compressing) a ferrule on to cable


Tangent – A line that touches a curve at a single point

Tangent Point – 1. The point on a curve at which a tangent line touches, 2. The point on the curve of an easement at which perpendicular cut to the tangent line at the rake angle that will provide a matching cross section to a square cut on the intersecting rake moulding of the same profile and a smooth transition or easing at the intersection

Tangent System of Handrailing – A plane geometry method of determining the face moulds for the construction of wreathed handrails utilizing tangents to develop the intersection of the planes that include all the points along the centerline of the handrail.

Terminal – 1. Hardware used at the ends of cable, sometimes also incorporating a tensioning device, 2. A fitting used to terminate a rail

Tight Set together so that there is no opening between members (Architectural Woodwork Institute, AWI®)

Tongue A projection on the edge or end of a wood part that is inserted into the groove or plow of a similar size to form a joint (Architectural Woodwork Institute, AWI®)

Tongue and Groove Joint A joint formed by the insertion of the “tongue” of one wood part into the “groove” of the other (Architectural Woodwork Institute, AWI®)

Tread – The horizontal walking surface of a stair

Tread, Bowed – A tread that is curved in plan view at the nosing edge

Tread Depth – The horizontal distance between two successive nosings on a stair, See GOING or RUN (UNIT RUN)

Tread, Engineered – A tread that is composed of a core material with balanced veneers applied to both faces to stabilize the product from warp and cup  

Tread, Hybrid – A tread made with finish quality material finger joined on the end(s) where exposed and a lower grade material where it will be concealed, by floor covering

Tread, Mitered Returned – A tread used on open stringer stairs with a return nosing applied to the end(s) to project over the open face string(s) matching the projection of the tread nosing at the riser.

Tread Return – A moulding matching the nosing moulding profile of the tread nosing that is shoulder mitered to the tread nosing at the end of a tread to eliminate exposed end grain and provide a continuation of the nosing profile and projection identical to the tread nosing.

Turnbuckle – Hardware used to, couple or tension cable; utilizing sleeves, swivels, and/or internal screws

Turnout – A starting rail fitting or starting step that turns 90 degrees to the starting newel offset beyond the width of the stair above


Up Easing – Used to describe an easing in a rail with the center of its arc above the top of the rail


Veneer A thin layer of wood, sliced from a log or flitch. Thickness may vary from, but not exceed, 0.3 mm [.012”] to 6.4 mm [.252”] thick. (Architectural Woodwork Institute, AWI®)

Volute A starting rail fitting that is designed as a spiral in plan view by connecting a series of 90-degree arcs diminishing in radius by a constant value or proportion.  Typically, a volute consists of some portion that is flat in the horizontal plane, called a scroll, connected to a wreath or easing portion that makes the transition to the connection with the rake rail.

Volute, Vertical – A starting rail fitting that is designed as a spiral in elevation by connecting a series of 90-degree arcs diminishing in radius by a constant value or proportion.

Volute, Lateral – A metal railing termination that is a horizontal scroll, See VOLUTE

Volute Step (Scroll Step) – A type of bullnose starting step with a nosing designed concentric to the plan view of the volute or scroll through at least 180-degrees.  Since the spiral of the nosing must be “curtailed” to maintain the integrity of the step these are sometimes called Curtail Steps.


Walk Line 1. The most common path of travel used in the design of winders determined by the distance from the handrail to the closest foot when the handrail is used in travel on a stairway, 2. A point at which winders are regulated for depth by building codes, measured 12 inches from the side of the stair where the treads are narrower, on that portion within the usable width, at the surface of the tread

Wall Rail – A handrail mounted to a wall.

Wash – The slight horizontal sloping of treads such that the leading edge is lowest to allow water to run off and to minimize wear at the nosing edge

Wedge – A piece of material tapering in thickness from end to end used to align or secure components

Well Hole or Well Opening – The opening in a floor through which a stairway ascends

Well Matched for Color and Grain Members that make up the components of an assembly and components of an adjacent assembly are: Similar and nearly uniform in color, and have similar grain, figure, and character. Adjacent members must be of the same grain type whether flat grain (plain sliced), vertical grain (quarter cut), rift grain, or mixed grain. (Architectural Woodwork Institute, AWI®)

Winder – A tread with nonparallel edges.

Winding Stair A stair that turns with winders

Work Surface A flat surface, typically horizontal, for supporting objects used in working; a surface for working on

Wreath 1. A handrail that has a curve in plan view and elevation referred to as double curvature or a compound curve, 2. A handrail or string transition that twists between a rake and level or two rakes at a curve in the plan view of the stair(s) or handrail

X   –    Y   –   Z


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