What term refers to an item used or carried by an actor during a performance?

The term that refers to an item used or carried by an actor during a performance is "prop." This is a broad term that encompasses any physical object that is utilized on stage to enhance the story or the character's actions. Props can range from small items, like a book or a cup, to larger set pieces.

Personal props may refer specifically to items that belong to a character, enhancing their individuality, but "prop" in its general form covers all items used by actors. Stage elements might refer to components of the overall set design or construction rather than individual items used by actors. Costume pieces, on the other hand, specifically refer to clothing and accessories worn by actors, not items they carry or use during their performance. Therefore, the broad and inclusive nature of the term "prop" makes it the most accurate choice in this context.