Spandrel
Pronunciation : Span"drel
Part of Speech : n.
Etymology : [From Span.]
Definition : 1. (Arch.)
Defn: 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]
Source : Webster's Unabridged Dictionary, 1913