Hand-knotted rugs are a type of rug made by tying individual knots to create the design. They are usually made from wool, cotton, or silk and are often used as decorative pieces in homes. The term 'ryas' is a type of hand-knotted rug that originated in the Middle East and is characterized by its intricate patterns and vibrant colors. Ryas are typically made with wool and are known for their durability and longevity.