Obligato

Part of speech: noun

Definitions

1. A musical line or passage that is indispensable and must be played as written
2. In music, a part that is necessary and cannot be left out of a performance
3. An essential instrumental or vocal component in a composition that must be performed exactly as indicated

Etymology: The word comes from Italian "obbligato", the past participle of "obbligare", meaning "to oblige" or "to bind". Its English twin is "obliged", and the two are doublets: they descend from the same Latin ancestor, "obligare", but reached English by different routes, one through French and one directly from Italian. In music, the Italian form carries a specific sense of "indispensable", so a part marked obbligato is one the composer required rather than an optional ornament. The English spelling "obligato" is an alternative to "obbligato", which keeps the double consonant of the Italian original. The term entered English as a musical borrowing, and the sense of "bound" in the Italian has become "bound to be played" in the score.

Synonyms: essential, mandatory, required, necessary, indispensable

Antonyms: optional, discretionary, unnecessary, voluntary, noncompulsory