The most common and most likely answer to this crossword clue is the 8 letter word SPANDREL
I've seen this crossword clue in The Times
S
P
A
N
D
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More clues leading to the result SPANDREL
Buddy explains!
The straight part
We know that "Overarching panel" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case overarching panel = spandrel.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SPANDREL mean?
SPANDREL noun- The space (often more or less triangular) between the outer curve of an arch (the extrados) and a straight-sided figure that bounds it; the space between two contiguous arches and a straight feature above them.
- Horizontal member between the windows of successive storeys of a tall building.
- The triangular space under a stair; the material that fills the space.
- An oriental rug having a pattern of arches; the design in the corners of such a rug, especially in a prayer rug.
- A phenotypic characteristic that evolved as a side effect of an adaptation in response to evolutionary pressure.