A saxophone is any of a family of single-reed wind instruments with a conical tube, usually made of brass, and which uses finger-operated keys with leather pads to open and close the approximately 24 toneholes in the body in order to change the effective length of the vibrating air column and thereby change the pitch. Saxophones are available in various sizes, from soprano to bass, and are nearly always treated as transposing instruments. Most have a distinctive upturned lower end and a detachable crook at the upper end.
Despite usually being made from brass, saxophones are classified as woodwind instruments rather than brass instruments because they generate sound with a single reed. The only other metallic woodwind is the flute, which was originally made entirely of wood. Because of its conical bore, saxophones have warmer and more mellow tone qualities than cylindrical bore woodwind instruments. Their great flexibility allows them to blend well with both woodwind and brass instruments.
The saxophone was invented by the Belgian instrument maker Adolphe Sax in the early 1840s for use by both military bands and orchestras. However, it never came into widespread use as an orchestral instrument, but is common in jazz and some other forms of popular music.