Shape of a wing, perhaps (5)
I believe the answer is:
delta
'shape' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'a wing perhaps' is the wordplay.
I cannot quite understand how this works, but
'a' is within the answer.
'wing' could be 'l' and 'l' is present in the answer.
The remaining letters 'det' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'of' acts as a link.
Can you help me to learn more?
(Other definitions for delta that I've seen before include "Area of distributaries in a river basin" , "Extended area at river mouth" , "Area of distributaries at a river mouth" , "Triangular patch of land at mouth of river" , "Estuary area where river has split" .)