Denim (which gets its name from the French town of Nîmes (de Nîmes))[citation needed] is a rugged cotton twill textile, in which the weft passes under two (twi- "double") or more warp threads. This produces the familiar diagonal ribbing identifiable on the reverse of the fabric, which distinguishes denim from cotton duck. Denim has been in American usage since the late 18th century.The word comes from the name of a sturdy fabric called serge, originally made in Nîmes, France, by the André family. Originally called serge de Nîmes, the name was soon shortened to denim. Denim was traditionally colored blue with indigo dye to make blue "jeans" Black denim, though "jean" then denoted a different, lighter cotton textile; the contemporary use of jean comes from the French word for Genoa, Italy (Gênes), where the first denim trousers were made.
Dry or raw denim, as opposed to washed denim, is a denim fabric that is not washed after being dyed during its production. Over time, denim will generally fade, which is often considered desirable. During the process of wear, it is typical to see fading on areas that generally receive the most stress, which includes the upper thighs (whiskers), the ankles (stacks) and behind the knees (honey combs).
After being crafted into an article of clothing, most denim is washed to make it softer and to reduce or eliminate shrinkage, which could cause an item to not fit after the owner washes it. In addition to being washed, non-dry denim is sometimes artificially "distressed" to achieve a worn look.
Much of the appeal of factory distressed denim is that it looks similar to dry denim that has, with time, faded. With dry denim, however, such fading is affected by the body of the person who wears the jeans and the activities of his or her daily life. This creates what many enthusiasts feel to be a more natural, unique look than pre-distressed denim[says who?].
To facilitate the natural distressing process, some wearers of dry denim will often abstain from washing their jeans for more than six months[citation needed], though it is not a necessity for fading.