The term orchestra derives from the Greekὀρχήστρα, the name for the area in front of an ancient Greek stage reserved
for the Greek chorus. (500-400 BC)
An orchestra is a large instrumental ensemble that contains 4 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, as may the concert harp and electronic instruments.