Overcast is a stitching technique that involves creating small up and down stitches to firmly fasten two material pieces together. This method gives resilience and prevents the material from fraying. The backstitch may be used for a range of stitching projects, such as sewing the hem, sewing appliques, or even making quilts. It gives a neat and professional look for the completed piece.

whipstitch WordReferencecom Dictionary of English