Catgut

Catgut is a cord made out of the natural fibers found in the intestinal walls of animals. The intestines are scrapped clean and the strands are then twisted together to make instrument strings. These strings were popular in classical instruments and acoustic guitars, although synthetic materials have become more common. And don’t worry about your kitty being used for instrument strings: “cat” in this sense is short for “cattle.” Catgut is usually made from sheep or goat intestines.