The term 'PART OF AN OPERA' can be summarized by two crossword solutions: ARIA (4 letters) and SCENA (5 letters). An ARIA is a self-contained piece for one voice, usually with orchestral accompaniment, from an opera, cantata, oratorio, or other large vocal work. It is typically a solo performance, often with a dramatic emotional content. A scena is a section of an opera or other musical work that is distinct from the rest of the work in terms of its music, lyrics, and/or dramatic content. It is usually longer than an ARIA and may include multiple characters.