A dressmaker is a skilled seamstress who is capable of executing a professionally finished garment. The dressmaker of the late 1800s and the dressmaker of the twenty-first century remain the same in that they must possess the ability to construct and fit a garment. Dressmakers often specialize in specific categories and price ranges. Seamstresses differ from tailors in that they are not as skilled in the craft of tailoring. Instead, they utilize their skill in handling softer fabrics with different finishing techniques than those used in tailored garments.
Historical Dictionary of the Fashion Industry. Francesca Sterlacci and Joanne Arbuckle.