radar (rāˈdär), n. [acronym from RAdio Detection And Ranging.]
1. An electronic device designed to detect objects at a distance, and determine their distance from the device, by transmitting a pulse of radio waves and measuring the time required for the echo of the pulse to return to the emitting device; as, “the radar showed a plane approaching rapidly”. For more information of radar, see the article What is Radar? (see radar.htm). [acronym]
[PJC]
2. The method of detecting objects, finding their distance, or determining their speed, by use of a radar1 device; as, “modern radar can detect objects as small as raindrops”.
[PJC]