The horn (also known as the French horn) is a metallic musical instrument made of brass. Brass tubes are wrapped into a coil and at the end of the tubing is a flared bell. Pitch of a horn is controlled via the following methods:

• The speed with which air passes through the instrument. This is controlled by the hornist's lungs.
• The player's embouchure , that is, the diameter and tension of the lips.
• Valves which route the air into extra lengths of brass tubing.

As the instrument's name implies, the ancestor of the horn were actual animal horns; this usage survives in instruments like the shofar (a ram's horn) which is used in Jewish religious ceremonies.

It was much later in 1818 that the German instrument manufacturers Heinrich Stölzel and Friedrich Blümel patented the first horn with valves. Piston valves were later developed by François Périnet in 1839.

Today the horn is most often found in orchestras and concert bands. Leopold Mozart, used horns to signify a hunt in his Jagdsinfonie and Handel used the horn extensively in his compositions. It plays a prominent role in Bach's Brandenburg Concerto no. 1 .