spandrel Meaning, Definition & Usage

  1. noun an approximately triangular surface area between two adjacent arches and the horizontal plane above them
    spandril.

WordNet

Span"drel noun
Etymology
From Span.
Definitions
  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 1913