In classical music an obbligato (Italian for obligatory, from Latin word obligare, to oblige) is an elaborate accompaniment part played by a single instrument. Originally indicated a passage of music that was to be played as written, without changes or omissions, as opposed to ad libitum. Classical music is a broad, somewhat imprecise term, referring to music produced in, or rooted in the traditions of, European art, ecclesiastical and concert music, encompassing a broad period from roughly 1000 to the present day. ... Latin is an ancient Indo-European language originally spoken in Latium, the region immediately surrounding Rome. ... In music accompaniment is the art of playing along with a soloist or ensemble, often known as the lead, in a supporting manner as well as the music thus played. ... A musical instrument is a device constructed or modified with the purpose of making music. ... Look up Passage in Wiktionary, the free dictionary This article needs to be cleaned up to conform to a higher standard of quality. ... Ad libitum is Latin for at ones pleasure, often shortened to Ad lib. ...

In music for voice with instruments, 'obbligato' refers to a prominent instrumental part in an aria or other number. The archetype of the obbligato part is the vocal solo which, with a basso continuo, constitutes the accompaniment of vast numbers of late Baroque arias and recitatives. An especially ornate violin obbligato appears in the Benedictus of Beethoven's Mass in D. Such parts were often less formal in the 19th century, but prominent obbligato writing for flute in particular is not unusual in Romantic opera-for example in the cadenza of the traditional version of the Mad Scene in Lucia di Lammermoor(1835)-and the cello and English horn are often assigned an obbligato role in melancholy contexts(Fuller, David. Obbligato. The New Grove Dictionary of Music and Musicians, Edited by Stanley Sadie. Second Edition, vol. 18 page 253).

An example of a well-known obbligato would be the piccolo obbligato in the trio of John Philip Sousa's march Stars and Stripes Foreveror the corno (horn) obbligato in Gustav Mahler's Symphony No. 5. Portrait of John Philip Sousa taken in 1900 John Philip Sousa (November 6, 1854 – March 6, 1932), popularly known as The March King, was an American composer and conductor of the late Romantic era known particularly for American military marches. ... The Stars and Stripes Forever is a patriotic American march. ... This article cites its sources but does not provide page references. ... The Symphony No. ...