Radar is an object-detection system that uses electromagnetic waves—specifically radio waves—to identify the range, altitude, direction or speed of both moving and fixed objects such as aircraft, ships, spacecraft, mountain ranges, radio and TV towers, guided missiles, motor vehicles, weather formations, and terrain. The radar dish, or antenna, transmits pulses of radio waves or microwaves which bounce off any object in their path. The object returns a tiny part of the wave's energy to a dish or antenna which is usually located at the same site as the transmitter.
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radar A system using beamed and reflected radiofrequency energy for detecting and locating objects, measuring distance or altitude, navigating, homing, bombing and other purposes.