A binding margin is the vertical space without any text, on each page, used for stitching, drilling or whatever method is used to hold the pages together. The binding margin is measured in characters or braille cells on an embosser, or in inches or millimeters on a printer. For single-sided work, the binding margin is the same thing as the left margin. For interpoint braille output, the binding margin is also the right margin on the back side of each sheet.