A horn section is a group of musicians playing horns. In an orchestra or concert band, it refers to the musicians who play the "French" horn, and in a British-style brass band it is the tenor horn players. In many popular-music genres the term is applied loosely to any group of woodwind or brass instruments, or a combination of woodwinds and brass.
In a symphony orchestra, the horn section is the group of symphonic musicians who play the French horn (or German horn or Vienna horn). These musicians are typically seated to the back of the ensemble and may be on either side at the director's discretion. Placing them to the left with their bells toward the audience increases the prominence of the section, whereas on the right, the sound reflects off the back of the stage. The order from the principal horn (first horn) to the fourth horn is right to left from the director's view. The section is ordered in this way so the principal horn may be heard by all players, as the principal sets the timbre and intonation of the section.
In the argot of American popular music, the word "horn" is used for any wind instrument, most often the saxophone, but it is also applied to all woodwinds and brasses, especially those played by soloists (Anon. 2013). In this context "horn section" refers to a group of wind and brass instrumentalists -- usually comprising saxophone, trumpet and trombone players; sometime singularly, and sometimes in pairs or more of each instrument. The horn section usually has written parts which are prepared by an arranger using orchestration to provide a harmonic and melodic accompaniment to a song or musical group. In some cases, the horn section may improvise a simple backing part using well-known "stock" lines.
Horn sections are an integral part of musical genres such as jazz, R&B, blues, funk, calypso, ska, soul music and gospel music. Most of these horn sections feature some combination of saxophones, trumpets and trombones. More rarely, other wind or brass instruments such as flute, clarinet or tuba may be added. Other popular musical genres, such as rock and pop, also use horn sections.
Horn sections in blues bands and funk groups may be composed of session musicians playing arranged parts, or they may be a consistent group of musicians. A small number of horn sections use a consistent group of musicians who become well known as a unit.