A guitar can be classified as a stringed instrument. This is such because its sound is produced from the vibrations of the strings. Interestingly enough, and as expected, guitars have many different types of strings however generally speaking there are 2 main types: steel and nylon.
Steel strings are used on both electrical and acoustic guitars, while nylon strings are primarily used for classical and flamenco guitars. Even though these strings are made with either steel or nylon, they’re almost always wound with either nickel, brass or copper alloys.