Obbligato
OBBLIGATO, or OBLIGATO, in the modern sense, a musical term (adopted from the Italian, and strictly meaning obligatory or binding) for an instrumental accompaniment to a musical composition which, while in one way independent, is included by the composer on purpose and in a prescribed form, instead of being left to the discretion (ad libitum) of a performer.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)
