Edgestitching is a speficic type of topstitchingSee Topstitching in the Sewing documentation. It is specific because of its location. To edgestitch means to topstitch right next to a seam, typically about 3mm or 1/8 inch next to it.
Edgestitching can be used to reinforce seams, to keep material in place by sewing down seam allowance or lining, and for decorative effect.
For best results, use a sewing needle for optimized for topstitching