Sentence:  When the <WSD>placket</WSD> of his shirt gave way, the stones tore freely into the skin on his chest and back, and he no longer imagined Lucy Hartley enjoying his guitar serenades—he wondered if he would get to the roof alive. 
Meaning of the word marked with <WSD> tags:  A slit or other opening in an item of clothing, to allow access to pockets or fastenings