A drawstring is material threaded through a casing, used to cinch or close something. They are used in sweatshirt hoods to help them fit snugly, in the waistline of garments as an alternative to elastic or a belt, and as means of closing and securing any kind of fabric sack, such as a purse or duffle bag.
Sports pants in jogging suits or sweatsuits, and medical pants, also called scrubs, are two popular garments in which one commonly finds a drawstring. When used to cinch the waist of a garment, it may either be partly visible as part of the garment's exterior design or threaded invisibly inside the garment. Many different narrow fabrics can serve as a drawstring, including cord, braid, leather, ribbons, and strips of fabric from which the garment is made. When the garment is being constructed, either a safety pin or a tool called a bodkin is used to pull the string through the casing. An external drawstring may be fastened by tying it in a bow or fastening it with a buckle, depending on is function, while an internal one is made to be tied.
Even with precautions, such as tying the ends of a drawstring before putting a garment in the wash, or making small knots in each end that will prevent it being pulled completely inside, the cord will occasionally get "lost" in a garment or even break. If you remove the old drawstring, using a large safety pin or a bodkin if you have one, you can rethread the casing with a new one.
Bags that use drawstrings for closure include sports backpacks for carrying gear from the locker room to the athletic field, fashionable purses, satchels, beach bags, holiday gift bags, duffel bags, and coin pouches. Since it is not the most secure or complete closure, you will find that some of these items use the drawstring only as an ornament, and that even if it is functional, some have a secondary fastening system, such as a snap or zipper.