Draw tops of the old windows (3)
I believe the answer is:
tow
'draw' is the definition.
(I know that tow is a type of draw)
'tops of the old windows' is the wordplay.
'tops of' indicates taking the first letters.
The first letters of 'the old windows' is 'TOW'.
(Other definitions for tow that I've seen before include "Drag along behind, say barge" , "form of flax" , "Pull away" , "Pull or drag along behind" , "Prepared fibres" .)