spandrel

spandrel

Roughly triangular area on either side of an arch, bounded by a line running horizontally through its apex, a line rising vertically from the springing of the arch, and the exterior curve of the arch. When arches adjoin, the entire area between their crowns and springing line is a spandrel. If filled in, as is ordinarily the case, the result is a spandrel wall; in medieval architecture this was usually ornamented. In buildings of more than one story, the spandrel is the area between the sill of a window and the head of the window below it. In steel or reinforced-concrete structures, a deep spandrel beam may span across this area. The triangular area of space beneath a stair is also known as a spandrel.

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spandrel [′span·drəl]

(building construction)

The part of a wall between the sill of a window and the head of the window below it.

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spandrel, spandril

spandrel, 1

1. An area, roughly triangular in shape, included between the extradoses of two adjoining arches and a line approximately connecting their crowns (or a space approximately equal to half this in the case of a single arch); in medieval architecture, often ornamented with tracery, etc.

2. In a multistory building, a wall panel filling the space between the top of the window in one story and the sill of the window in the story above.

3. A surface, roughly triangular in shape, as below a stair string.