Baluster/SpindleA plain or decorative vertical post that acts as the infill between the handrail and base rail or treads if used with cut string.

BalustradingThe name given to a complete assembly of handrails, base rails, newels, spindles, and caps.

Baserail: A long length of timber fitted on top of the stringer (string) between the newel posts that hold the bottom of the balusters/spindles.

Bullnose Step: Normally added to the bottom of a flight of stairs. A bullnose step can have one or both ends of the step with a quarter circle design.

Continuous Handrail:  Using straight lengths of handrail connected to handrail fittings and ramps, the handrail flows over the tops of newel turnings creating a continuous run of the handrail.

Curtail Step:  A decorative shaped step at the bottom of the staircase usually accommodating the volute and volute newel turning of the continuous handrail system

Flight: A set of steps leading from one floor to another floor.

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

Glue Blocks: Blocks of wood attached to the underside of a stair at the concealed junction of the risers, treads, and or stringers to minimise movement that may cause squeaks and creeps in your staircase.

Going: In relation to a flight of stairs. This is the horizontal distance between the face of the first and last risers. (See run, tread depth)

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

Handrail: A sloped or horizontal rail intended for holding by the hand as climb or descend stairs; for guidance, support, pulling, or arresting a fall. Part of The railing used as support in balustrade systems

Headroom: a) The clear vertical space allowed for passengers on a stairway to prevent hitting of the head. b) The vertical distance from the plane of the nosings of a flight of stairs, 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.

Infill:  A wooden strip that fills the space between spindles in both the baserail and underside of the handrail.  (Sometimes called a  fillet) but we ain’t having fish today.

Landing: An intermediate level area between floor levels connecting flights of stairs
a) Quarter landing: The width of one flight of stairs.
b) Half landing: The width of two flights of stairs.

Newel Cap: The decorative top or cap of a newel post. Available in many styles.

Newel PostA post, usually at the head or foot of a flight of stairs, Accommodates the handrail. Also, can accommodate the strings of stairs.

NosingThe edge of a tread on a flight of stairs, projecting beyond the face of the riser and the face of a cut string.

Pitch: The angle between the pitch line and the horizontal. (also see Rake)

Pitch Line: The imaginary line connecting the nosing of all treads in a flight of stairs

Rail System/Railings:

Rake: Also meaning the pitch of the stairs.

Rise: a) The rise of a flight is the vertical distance between the floors or landings connected by the flight. b) The individual is the vertical measurement rise between the tops of two consecutive treads.

Riser The board that forms the face of each individual step.

Routed String:

Run: Is a single flight of stairs or steps between landings.

String: The long lengths of timber either side of a staircase which supports the staircase structure. The three types are:
a) Closed String: A string with the face milled to accommodate treads and risers so their profile cannot be seen.
b) Cut or Open String: A string with the upper edge cut away to the shape of the treads and risers so that their profile can be seen from the side.
c) Wall String: The string of a staircase fixed flush with a wall. Can be used on both sides of a staircase.

Soffit: A term used to describe the material that covers the underside of a staircase.

Spandrel: 

Stairway/StairwellThe space or void provided between floors for the staircase.

Spiral Staircase: An often decorative staircase that, as it rises turning constantly around a central axis (which may be a solid axis or an open centre).

Tread: The top of a step or horizontal surface of a step.

Tread Depth:

Up-Ramp :

Wall Rail:

Wall Rail Brackets:

Wall String:

Winders: Radiating stair steps smaller at one end. Used to change the direction of flights of stairs through 90° or 180°.