[ob-li-gah-toh; It. awb-blee-gah-taw] 
adjective, noun, plural -tos, -ti [-tee] . Music.| 1. | (used as a musical direction) obligatory or indispensable; so important that it cannot be omitted. |
| 2. | an obbligato part or accompaniment. |
| 3. | a continuing or persistent subordinate or background motif. |
| 4. | a subordinate part of a solo. |
| ob·bli·ga·to also ob·li·ga·to (ŏb'lĭ-gä'tō) adj. Not to be left out; indispensable. Used of an accompaniment that is an integral part of a piece. n. pl. ob·bli·ga·tos also ob·li·ga·tos or ob·bli·ga·ti also ob·li·ga·ti (-tē) An obbligato accompaniment. [Italian, past participle of obbligare, to obligate, from Latin obligāre, to oblige; see oblige.] |
obbligato
(Italian: "obligatory"), in music, essential but subordinate instrumental part. For example, in an 18th-century aria with trumpet obbligato, the trumpet part, although serving as accompaniment to the voice, may be as brilliant in its writing as that of the voice itself. The term obbligato accompaniment has a more specialized meaning in some 18th-century music (see accompaniment)
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lɪˈgɑ