Sentence:  His hand went to her shoulder and pushed aside the knotted scarf that surmounted the striped poplin gown ; then , to better purpose , he took hold of the <WSD>knot</WSD> and with dextrous fingers , untied it . 
Meaning of the word marked with <WSD> tags:  any of various fastenings formed by looping and tying a rope (or cord) upon itself or to another rope or to another object