One of the most basic embroidery stitches. Worked from left to right. The needle is brought through from the back of the fabric a small distance from the starting point of the line to be covered. The needle is inserted at the beginning of the line, so the stitch is being created in the opposite direction of the actual line to be stitched. For the next stitch, the needle is brought through the fabric at a distance equal in length to the first stitch. The needle is then inserted in the same hole as the beginning of the stitch before it.
Mary Thomas's Dictionary of Embroidery Stitches, p 3-4 [Point de Sable, Stitching, Back Stitch*]