Meaning mottled (from the Persian), the term refers to uneven coloration within monochrome areas, for example, on a solid-color central field of a Persian or Turkish carpet. Abrash may sometimes be an accidental effect of a weaver’s process-using yarns of the same color dyed in different dyebaths-but it was often used deliberately as an aesthetic choice: it creates a lively and variegated plane of color, adding depth and visual interest.
Elena Phipps, Looking at Textiles: A Guide to the Technical Terms. Los Angeles, Calif: The J. Paul Getty Museum, 2011.