Usually just "cyc" (rhymes with 'bike'). A plain cloth or plastered wall filling the rear of the stage. The term is often loosely applied to a blue skydrop, or any flattage at the rear of the stage. May be curved at the ends--and indeed the original sense of the word was a curving or u-shaped curtain. Typical made of canvas or heavyweight cotton duck, suspended from the grid, and reaching to the floor. The term "cyclorama" is also used to refer to the lighting instrument that covers the actual "cyc" with light. Newer models of these instruments include LED styles that require far less energy, and produce far less heat. Some are multifunction devices: dimmer, infinite-shades color changer, light source projector, strobe effect and optics with precision adjustment.