Answer: spandril

AnswerCrossword Clue
spandril(in a steel-framed building) a panellike area between the head of a window on one level and the sill of a window immediately above
spandrila space between two adjoining arches, also SPANDREL
spandrilthe decoration occupying the space at the corner of a stamp between the border and an oval or circular central design
spandrilarea between the extradoses of two adjoining arches, or between the extrados of an arch and a perpendicular through the extrados at the springing line