The word orchestra means a group of performers playing various musical instruments including stringed instruments of viol class, cornets and trombones, clarinets and flutes, drums, cymbals for playing music, as operas, symphonies, popular music or any other compositions. In a modern theater, the space reserved for the musicians is called the opera pit. The Opera pit is usually the front part of the main floor. A full size orchestra is about a 100 players. It is sometimes called a "symphony orchestra" or "philharmonic orchestra"; there is not fixed difference between the two in terms of instrumental constitution or the role of the orchestra.