Obligatos

Part of speech: noun

Definitions

1. A musical term referring to an essential melodic line that complements the main theme
2. describing a musical accompaniment that is indispensable for the piece's expression
3. indicating parts in compositions that are not merely optional, but rather critical for the overall sound

Etymology: "Obligatos" is the plural of "obligato," so the history belongs to that base word. "Obligato" is an Italian musical term, the past participle of "obbligare," meaning "to bind" or "to oblige," which came from Latin "obligare," "to bind together." In music it describes a part that is not optional: a line the performer must play, as opposed to an ad libitum passage that can be omitted or improvised. The plural form is used when several such parts appear together in a score, as in an ensemble or concerto where more than one instrument carries an indispensable line.