The term SOUND OF MUSIC EXTRA can be summarized as a NUN, which is a three letter word. A NUN is a member of a religious community of women who live a cloistered life and take vows of poverty, chastity, and obedience. Nuns are often associated with the Catholic Church, but there are also many other religious orders of nuns in other denominations. The Sound of Music is a classic musical film released in 1965, starring Julie Andrews as Maria, a young NUN who leaves her convent to become a governess for the Von Trapp family. The Sound of Music Extra refers to any additional cast members or crew who worked on the film.