Scenery is the "background" for a scene in a play, movie, or themed environment. It is made up of backdrops, painted flats suspended from above, and large free-standing set pieces that the actors might climb upon or inside. (Props, a related subject, consist of smaller items that are hand-held, or furniture such as tables and chairs.)
A typical scenic studio might offer design services as well as construction and installation. They might serve only the theatre industry, or only television, or some combination of several industries. Some companies offer scenic elements, such as doors or realistic-looking rocks surfaces, instead of building entire sets.