selvage

noun

1. The edge of a woven fabric, where the weft (side-to-side) threads run around the warp (top to bottom) threads, creating a finished edge.
2. Any edge of fabric finished so as to prevent raveling.
3. The excess area of any printed or perforated sheet, such as the border on a sheet of postage stamps or the wide margins of an engraving.
4. A distinct border of a mass of igneous rock. It is usually fine-grained or glassy due to rapid cooling.