An [?] is an instrumental ensemble, usually fairly large with [?], [?], [?] sections, and almost always a [?] section as well. The term orchestra derives from the name for the area in front of an ancient Greek stage reserved for the Greek [?]. The orchestra grew by accretion throughout the eighteenth and nineteenth centuries, but changed very little in composition during the course of the twentieth century.

A smaller-sized orchestra for this time period (of about fifty players or fewer) is called a [?] orchestra.

A full-size orchestra (about 100 [?]) may sometimes be called a "[?] orchestra" or "philharmonic orchestra".