Pillowcase material can include percale (7 letters) and MUSLIN (6 letters). Percale is a closely woven, plain-weave fabric made from cotton or cotton-blend yarns. It is lightweight and breathable, making it a popular choice for bedding. MUSLIN is a lightweight, plain-weave fabric made from cotton or cotton-blend yarns. It is often used in quilting and dressmaking, but is also a popular choice for pillowcases due to its softness and breathability.