The xylophone is a musical instrument

Musical instrument

A musical instrument is a device created or adapted for the purpose of making musical sounds. In principle, any object that produces sound can serve as a musical instrument—it is through purpose that the object becomes a musical instrument. The history of musical instruments dates back to the...

 in the percussion

Percussion instrument

A percussion instrument is any object which produces a sound when hit with an implement or when it is shaken, rubbed, scraped, or otherwise acted upon in a way that sets the object into vibration...

 family that consists of wooden (not steel) bars struck by mallets. Each bar is an idiophone

Idiophone

An idiophone is any musical instrument which creates sound primarily by way of the instrument's vibrating, without the use of strings or membranes. It is the first of the four main divisions in the original Hornbostel-Sachs scheme of musical instrument classification...

 tuned to a pitch of a musical scale

Musical scale

In music, a scale is a sequence of musical notes in ascending and descending order. Most commonly, especially in the context of the common practice period, the notes of a scale will belong to a single key, thus providing material for or being used to conveniently represent part or all of a musical...

, whether pentatonic

Pentatonic scale

A pentatonic scale is a musical scale with five notes per octave in contrast to a heptatonic scale such as the major scale and minor scale...

 or heptatonic

Heptatonic scale

A heptatonic scale is a musical scale with seven pitches per octave. Among the most famous of these are the major scale, C D E F G A B C; the melodic minor scale, C D E F G A B C ascending, C B A G F E D C descending; the harmonic minor scale, C D E F G A B C; and a scale variously known as the...

 in the case of many African and Asian instruments, diatonic

Diatonic scale

In music theory, a diatonic scale is a seven note, octave-repeating musical scale comprising five whole steps and two half steps for each octave, in which the two half steps are separated from each other by either two or three whole steps...

 in many western children's instruments, or chromatic

Chromatic scale

The chromatic scale is a musical scale with twelve pitches, each a semitone apart. On a modern piano or other equal-tempered instrument, all the half steps are the same size...

 for orchestral use. The term may be used generally, to include all such instruments, such as the marimba

Marimba

The marimba is a musical instrument in the percussion family. It consists of a set of wooden keys or bars with resonators. The bars are struck with mallets to produce musical tones. The keys are arranged as those of a piano, with the accidentals raised vertically and overlapping the natural keys ...

 and balafon

Balafon

The balafon is a resonated frame, wooden keyed percussion idiophone of West Africa; part of the idiophone family of tuned percussion instruments that includes the xylophone, marimba, glockenspiel, and the vibraphone...

 or, more specifically, to refer to an orchestral instrument of somewhat higher pitch range than the chromatic marimba.