The term Wagner Opus is a reference to the works of German composer Richard Wagner. The crossword solutions for this term are LIBRETTO (8 letters) and OPERA (5 letters). LIBRETTO is the text of an OPERA, oratorio, or other kind of musical drama, while OPERA is a form of theatre in which music has a leading role and the parts are taken by singers. Wagner Opus is therefore a reference to the operas and other musical dramas composed by Wagner.