Denim is a rugged cotton twill fabric most commonly used for jeans. It was invented in California in the 1850s by Levi Strauss and remains popular worldwide. Denim is made from cotton that is dyed blue using indigo dye before being woven. The manufacturing process involves spinning cotton yarn, dyeing the warp yarns blue with indigo, sizing the yarns, weaving the fabric using a twill weave, and finishing the fabric with treatments like stone washing to create different looks. Denim is versatile and commonly used for jeans, jackets, bags, upholstery and more. It remains one of the most popular fabrics globally.