What is a casing in sewing?

A casing in sewing refers specifically to a closed tunnel of fabric designed to hold a piece of elastic or a drawstring. This technique is commonly used in waistbands of skirts, pants, and shorts, as well as in the openings of hoods or cuffs, allowing for gather or fit adjustments without the need for closures like zippers or buttons. The casing provides structure and support, ensuring that the elastic or drawstring stays securely in place while also allowing the garment to fit comfortably around the body. This method is essential for creating adjustable and fitted clothing designs, making it a fundamental concept in garment construction.