How do opera and oratorio differ in their usual performance settings?

In the context of vocal music, opera and oratorio are distinguished primarily by their performance settings and theatrical requirements.1

• Opera: This is a staged drama intended for performance in a theatre. It relies on a full theatrical production, which includes scenery, costumes, movement, and staged action to support the narrative.12
• Oratorio: This is considered a concert piece. While it utilizes a dramatic method to tell a story, it is not intended for liturgical use and may be performed in either churches or concert halls. Unlike opera, oratorio is generally performed without the elaborate theatrical staging, scenery, or costumes associated with the opera house.13

While both forms share musical elements such as recitative, arias, and orchestral accompaniment, the oratorio’s lack of required stage action is a defining characteristic that separates it from the fully realized theatrical experience of opera.13