Sliding window frame (4)
I believe the answer is:
sash
'sliding window frame' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sash that I've seen before include "Framework holding window panes" , "Piece of cloth round waist or shoulder" , "Ribbon worn over the shoulder" , "Strip of cloth - type of window" , "Band of cloth" .)