Sentence:  She chiefly recalled the Square under snow; cold mornings, and the coldness of the oil-cloth at the window, and the draught of cold air through the ill-fitting <WSD>sash</WSD> (it was put right now)! 
Meaning of the word marked with <WSD> tags:  The opening part (casement) of a window usually containing the glass panes, hinged to the jamb, or sliding up and down as in a sash window.