Nylon is a fabric that's woven from man-made fibers. The great thing about your polka dotted nylon shirt is that you can throw it in the in wash instead of getting it dry cleaned.
Many clothes are made from nylon, as opposed to natural fibers like cotton, silk. Women's stockings are sometimes called nylons, but they were usually made from silk before the twentieth century invention of the cheaper and more durable nylon. Because nylon is a kind of sturdy woven plastic, it's also used to make things like car parts, food packaging, and the strings of instruments. Nylon, modeled on words like "cotton" and "rayon," is a completely made-up word, with no real roots.