An overstitch is a type of sewing technique used to secure the edges of fabric and prevent fraying. It involves stitching over the edge of the fabric, creating a series of small, overlapping stitches that provide both durability and a decorative finish. This technique is commonly used in garments, upholstery, and crafts, enhancing the strength and appearance of seams. Overstitching can be done by hand or with a sewing machine, depending on the project.