radar: Radar is a system used to locate distant objects by bouncing radio waves off them. The equipment used to transmit and receive the radio waves is also called radar. Radar is short for RAdio Direction And Ranging. It works by transmitting radio waves from an antenna. The waves are reflected back when they strike something. Some of them return to the transmitter, where they are detected by a receiver. The length of time between sending and receiving indicates the distance between the object and the device. Radar has been used to help ships navigate and to map the surface of Venus.
