An overlock stitch is a type of stitch commonly used in sewing to finish the edges of fabric. It prevents fraying and provides a clean, professional look to seams. This stitch is typically created using an overlock sewing machine, which can sew, trim, and overcast the fabric edges simultaneously. Overlock stitches are especially popular in the garment industry for knit fabrics, as they allow for stretch and flexibility. The stitch can vary in complexity, with different numbers of threads used, resulting in various finishes. Overall, the overlock stitch is essential for durable and polished sewing projects.