Shopping for a kimono, you may see one in the window (4)
I believe the answer is:
sash
'window' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for sash that I've seen before include "Broad band, the one me father wore?" , "Window frame; silk band" , "Frame for a windowpane" , "Long strip of material - window frame" , "Waistband - type of window" .)