What classification of instrument is the French horn?

The French horn is a brass instrument made of tubing wrapped into a coil with a flared bell. The double horn in F/B♭ is the horn most often used by players in professional orchestras and bands, although the descant and triple horn have become increasingly popular.

Early metal horns were less complex than modern horns, consisting of brass tubes, wound around a few times, with a slightly flared opening (the bell). These early "hunting" horns were originally played on a hunt, often while mounted, and the sound they produced was called a recheat). Change of pitch was controlled entirely by the lips (the horn not being equipped with valves until the 19th century. Without valves, only the notes within the harmonic series are available. By combining a long length with a narrow bore, the French horn's design allows the player to easily reach the higher overtones which differ by whole tones or less, thus making it capable of playing melodies before valves were invented.

A crucial element in playing the horn deals with the mouthpiece. Most of the time, the mouthpiece is placed in the exact center of the lips, but, because of differences in the formation of the lips and teeth of different players, some tend to play with the mouthpiece slightly off center. Although the exact side-to-side placement of the mouthpiece varies for most horn players, the up-and-down placement of the mouthpiece is generally two-thirds on the upper lip and one-third on the lower lip.