The amount that the stitching line comes in from the edge. Standard seam allowance is 15 mm. Also referred to as the "left over" material when two pieces of fabric are sewn together.
Also called "SA" for short. A seam allowance is the distance between the seam line (where you stitch to join two or more pieces of fabric) and the cut edge of the fabric. General sewing term.
The width of fabric between the stitching line and the cutting line.