An orchestra is an ensemble of musicians who play musical compositions which are designed to be performed by a large group of instruments. In order to be considered an orchestra, the ensemble must have several sections, including string instruments, woodwinds, and brass instruments, with most orchestras also having a percussion section. Orchestras are led by a conductor in performance, and they can perform a wide variety of musical pieces at all sorts of events.

The term “orchestra” is derived from the Greek word for the area of the stage where the chorus sang and danced during performances in Ancient Greece. In staged performances with an orchestra, the musicians are classically positioned in a pit in the front of the stage which closely mirrors the design used in Greece. While performing on its own for a concert, an orchestra is often positioned on a stage so that people can see the musicians.

If an orchestra has less than 50 players, it is known as a chamber orchestra. Chamber orchestras can vary widely in size, and they may have more than 50 players on staff, allowing for substitutions as needed while providing a pool of specialized talent. A harpist, for example, may be necessary in some pieces but not in others. Chamber orchestras tend to perform smaller, more intimate pieces. Music for chamber orchestra can get quite complex, especially when it calls for a large complement of players.

Orchestras with 100 or more members are known as “full” orchestras, and they are sometimes referred to as symphony orchestras or philharmonic orchestras. There is no difference between a philharmonic and a symphony orchestra, and in fact some cities have one of each, with people using the terms to differentiate between two different groups of performers. Ballets, operas, and other performances which include music are often performed with a chamber orchestra, rather than a full orchestra, depending on the composition being performed.

The huge ensemble of instruments in a full orchestra can allow the orchestra to perform very large and very complex pieces. Various sections can harmonize with each other in a variety of ways, and the orchestra may be supplemented with a chorus for works which include vocal elements. Some of the greatest works of classical music were composed for full orchestras, and seeing them in person can be a very illuminating experience, as watching the orchestra can provide interesting clues into the ways that the different sections work with each other.