Place for a flowerpot (4)
I believe the answer is:
sill
'place for a flowerpot' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sill that I've seen before include "Ledge beneath a window" , "Shelf at the foot of a window" , "Underwater rock ledge" , "Window edge" , "Slab at foot of window" .)