A three-dimensional framework in which all the members are interconnected, designed to cover very large areas.
Spandrels
Roughly triangular spaces between an arch and its containing rectangle, or between adjacent arches. Also non-structural panels under the windows, especially on a curtain-walled building.
Spere
A fixed structure screening the lower end of the great hall from the screens passage. Spere truss: roof truss incorporated in the spere.
Spike
A thin spire of timber and lead, rising from the centre of a tower roof.
Spiral stair
A stair in a circular well with a central supporting newel. Also called a vice or (Scots) turnpike stair.
Spire
Tall pyramidal or conical feature crowning a tower or turret. Broach: starting from a square base, then carried into an octagonal section by means of triangular faces. Splayed-foot: variation of the broach form, found in England principally in the south-east, in which the four cardinal faces are splayed out near their bases, to cover the corners, while oblique (or intermediate) faces taper away to a point. Needle spire: thin spire rising from the centre of a tower roof, well inside the parapet.
Spirelet
Slender spire on the ridge of a roof. Also called a fleche.
Splat
A flat board with shaped sides, especially a baluster (called a splat baluster).