A percussion instrument is a musical instrument that is sounded by being struck or scraped or struck by a beater. This includes attached or enclosed beaters or rattles that are struck by hand or by another similar instrument. The percussion family is believed to include the oldest musical instruments, following the human voice.
The percussion section of an orchestra most commonly contains instruments such as timpani, snare drum, bass drum, cymbals, triangle and tambourine. However, the section can also contain non-percussive instruments, such as whistles and sirens, or a blown conch shell.
Percussive techniques can also be applied to the human body, as in body percussion. On the other hand, keyboard instruments, such as the celesta, are not normally part of the percussion section, but keyboard percussion instruments such as the glockenspiel and xylophone (which do not have piano keyboards) are included.
These three groups overlap heavily, but inclusion in any one is sufficient for an instrument to be included in this list. However, when only a specific subtype of the instrument qualifies as a percussion instrument, only that subtype is listed here.
For example, a samba whistle [or apito] is an un-pitched percussion instrument, but a whistle in general is not.