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Webster 1913 Edition
Spandrel
1.
(Arch.)
The irregular triangular space between the curve of an arch and the inclosing right angle; or the space between the outer moldings of two contiguous arches and a horizontal line above them, or another arch above and inclosing them.
2.
A narrow mat or passe partout for a picture.
[Cant]
Webster 1828 Edition
Spandrel
SPAN'DREL
,Noun.