There are four or five accepted and cognate meanings of spandrel in architectural and art history, all relating to the space between a curved figure and a rectangular boundary - such as the space between the curve of an arch and a rectilinear bounding moulding, or the wallspace bounded by adjacent arches in an arcade and the stringcourse or moulding above them, or the space between the central medallion of a carpet and its rectangular corners.
The spandrels over doorways in Perpendicular work are generally richly decorated. At Magdalen College, Oxford, is one which is perforated, and has a most beautiful effect. The spandril of doors is sometimes ornamented in the Decorated period, but seldom forms part of the composition of the doorway itself, being generally over the label.
See also: Cathedral architecture
Another usage of the word spandrel was popularized by Stephen Jay Gould and Richard Lewontin in the paper "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme". In the context of evolution, a spandrel is a metaphor for characteristics that are or were originally side effects and not true adaptations to the environment.
They are analogous to misbugs in hacker jargon.
This metaphorical meaning works no matter which kind of architectural spandrel is referred to: the spandrel is the un-designed gap between other features, which is then often exploited for a use of its own.
Reference: Stephen Jay Gould and Richard C. Lewontin. "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme." Proc. Roy. Soc. London B 205 (1979) pp. 581-598External link
This article incorporates material from a 1911 encyclopedia. Please update as needed.