Small wooden frame? (4)

I believe the answer is:

sash

'frame?' is the definition.
(I know that sash is a type of frame)

'small wooden' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'wooden' becomes 'ash' (made of ash).
's'+'ash'='SASH'

(Other definitions for sash that I've seen before include "Window frame - shoulder band" , "Band - scarf" , "seen hanging around Miss World?" , "type of cord?" , "Decoration for the twelfth" .)

I've seen this clue in the Evening Standard.

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