nne Opera adaptations

Reitz, J.M. ODLIS : online dictionary for library and information science, July 25, 2014 (adaptation: A work that has been edited or rewritten, in part or in its entirety, for a new use, audience, or purpose. Also, a work converted to another literary form or artistic medium to serve a different or related purpose, while retaining as much of the action, characters, language, and tone of the original as possible, for example, a novel or story adapted for performance on the stage, a play adapted for the motion picture screen, or an engraving based on a painting. In music, a work that is a distinct alteration of another musical work (for example, a free transcription), or that paraphrases parts of various works or imitates the style of another composer, or that is somehow based on another musical work)
RDA glossary, viewed July 30, 2014 (Adaptation: 1) A new derivative work created by revision of a previously existing work that substantially changes the nature and content of that work. 2) In the case of a musical work, a derivative work described as freely transcribed, based on, etc.; a revision incorporating new material; a paraphrase of various works by, or in the general style of, another composer; revisions in which the harmony or musical style of the original has been changed; performances involving substantial creative responsibility for adaptation, improvisation, etc., on the part of the performer or performers; or any other distinct alteration of another musical work.)
Görlach, M. An alphabetical list of English text types, in Text types and the history of English, c2004: p. 24 (adaptation: something adapted)

Paraphrases, rewritings, etc., that are intended for a different audience or purpose, or are in a different form, from the original.