lə̇ˈbred.(ˌ)]ō, -e(ˌ)t] noun
( plural libret·tos ]ōz ; or libret·ti ]ē)
Etymology: Italian, diminutive of libro book, from Latin libr-, liber — more at leaf
1. : the text of a work (as an opera) for the musical theater
2. : the book containing a libretto