A cornet is a brass musical instrument that resembles a trumpet but has a more conical shape. It is commonly used in concert bands, brass bands, and orchestras. The cornet produces a warm, rich sound and is played by buzzing the lips into a mouthpiece while pressing valves to change notes. The cornet is often made of brass and can be found in various keys, with the B♭ cornet being the most popular. It is closely related to other brass instruments like the trumpet and flugelhorn, and it plays an essential role in both classical and jazz music settings.