An
orchestra ( or ; ) is a large
instrumental ensemble used in
classical music that contains sections of
string (
violin,
viola,
cello and
double bass),
brass,
woodwind, and
percussion instruments. Other instruments such as the
piano and
celesta may sometimes be grouped into a fifth section such as a
keyboard section or may stand alone, as may the
concert harp and, for 20th and 21st century compositions,
electric and electronic instruments. The term
orchestra derives from the
Greek ὀρχήστρα, the name for the area in front of an
ancient Greek stage reserved for the
Greek chorus. The orchestra grew by accretion throughout the 18th and 19th centuries, but changed very little in composition during the course of the 20th century.
