Nylon is a material that people make clothes, bags, and other things out of. It's kind of like plastic, but it's softer and stretchier.
To make nylon, people start with things called "polymers" which are long chains of molecules. They mix these polymers with special chemicals and heat them up until they melt. Then they push the melted mixture through tiny holes to make thin strings.
Once those strings cool down, people can twist them together to make thicker strings. They can also weave a bunch of those strings together to make fabric.
Nylon is a good material because it's strong and can stretch without breaking. It's also easy to clean and doesn't wrinkle too much. So people like using it for things they use a lot, like backpacks or athletic clothes.