Not all kilts are made from tartan, although tartan is the defining fabric of traditional kilts. While traditional kilts are almost always made from woven wool tartan, many modern styles such as utility and contemporary kilts are made from solid-colored or non-tartan materials like poly-cotton, ripstop, canvas, denim, or other durable fabrics. Hybrid kilts may combine tartan with these modern materials, but tartan itself is not required for a garment to be considered a kilt. The use of tartan is closely tied to tradition and formal wear, while non-tartan kilts are typically designed for everyday use or modern styling.