Opera (Italian: [ˈɔːpera]; English plural: operas; Italian plural: opere [ˈɔːpere]) is a form of theatre in which music has a leading role and the parts are taken by singers. Such a 'work' (the literal translation of 'opera') is typically a collaboration between a composer and a librettist and incorporates a number of the performing arts, such as acting, scenery, costumes and sometimes dance or ballet. The performance is typically given in an opera house, accompanied by an orchestra or smaller musical ensemble, which since the early 19th century has been led by a conductor.