The term 'airport device' can be summarized as a RADAR, which is a five-letter word. RADAR is an electronic system used to detect the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. It works by sending out radio waves and detecting any that are reflected back, allowing it to measure the distance and other characteristics of the object. RADAR is used in many applications, including air traffic control, navigation, and weather forecasting.