"Joseph and the amazing technicolor dreamcoat" is entirely sung (Well, apart from "and I don't speak Egyptian very well"), but is usually referred to as a music

"Joseph and the amazing technicolor dreamcoat" is entirely sung (Well, apart from "and I don't speak Egyptian very well"), but is usually referred to as a musical. Maybe just marketing though. Personally I usually expect opera to mean a particular style of singing more than anything else.