IPA: /ˈspændrəl/
KK: /ˈspændrəl/
A triangular area found between the curve of an arch and the surrounding structure, often seen in architecture. It can also refer to the space between two arches and a horizontal feature above them.
The architect designed beautiful decorations in the spandrels of the arches.
Spandrel comes from the Middle French 'spandrel' (meaning a triangular space), which is derived from the Old French 'espandrel' (meaning to spread out). The word refers to the space between the curve of an arch and the rectangular framework that surrounds it, thus describing a space that spreads out between two structures.
Imagine a triangular space that 'spreads out' between an arch and its frame — that's what a spandrel is.