Etymology

Noun

1. A large group of musicians who play together on various instruments, usually including some from strings, woodwind, brass and/or percussion; the instruments played by such a group.
2. A semicircular space in front of the stage used by the chorus in Ancient Greek and Hellenistic theatres.
3. The area in a theatre or concert hall where the musicians sit, immediately in front of and below the stage, sometimes (also) used by other performers.

Usage notes

• In British English, "The orchestra are tuning up" is often used, implying the individual members. In the US, one would almost always hear "The orchestra is tuning up", implying a collective.