The musical instrument that has four strings is known as a violin. It is a high-pitched string instrument that is played with a bow made of horsehair. The four strings of the violin are tuned to the notes G, D, A, and E, and are played by pressing down on them with the left-hand fingers while bowing with the right-hand. The violin is commonly used in classical music, but can also be found in folk, jazz, and popular music genres.