The term 'theatrical backdrop' refers to the background scenery used in theatrical performances. The three crossword solutions for this term are ARRAS (5 letters), SCRIM (5 letters), and SET (3 letters). ARRAS is a type of tapestry or wall hanging that is often used as a backdrop in theatrical performances. SCRIM is a type of fabric that is often used as a backdrop in theatrical performances, as it can be lit from behind to create a variety of lighting effects. Finally, a SET is a physical structure that is built to represent a location or environment in a theatrical performance.