What is a standard background set unit commonly called?

A standard background set unit is commonly referred to as a flat. In the context of film and television production, a flat is typically a large, lightweight frame covered with material such as canvas or plywood, which can be painted or styled to represent walls or scenery on set. Flats are essential for creating the illusion of space within the set and are designed to be easily movable and reconfigurable, making them very practical for various scenes and setups.

While green screens and backdrops serve similar purposes in providing backgrounds, they are more specialized. A green screen is specifically used for chroma keying, allowing the insertion of digital backgrounds during post-production. A backdrop, on the other hand, usually refers to a decorative screen used behind subjects in photography or video, but it may not have the same structural aspects as a flat. A screening room is a space specifically designed for watching films and generally does not refer to a physical background unit used in production.