A libretto is the text used in an extended musical work such as an opera, operetta, musical, masque, sacred or secular oratorio and cantata, musical, and ballet. The term "libretto" is also sometimes used to refer to the text of major liturgical works, such as mass and requiem. "Libretto" (pl. libretti) is an Italian word which translates literally as "little book." It is distinct from a synopsis or scenario of the plot. Wikipedia
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