"RYG" stands for "Red-Yellow-Green," which are the colors of a traffic light. The term "traffic light" is a commonly used synonym for "RYG" as it refers to the same object. "Semaphore" is another synonym for "RYG" and is also a type of traffic signal. "Stoplight" is another term that is widely used to describe "RYG" as it refers to the same traffic signal. "Traffic signal" is another commonly used synonym for "RYG," although it can refer to any type of traffic signal regardless of the color or pattern. "Traffic control device" is also a synonym for "RYG" as it is a general term used to refer to any object or device used for controlling traffic.