radar

radar
    n 1: measuring instrument in which the echo of a pulse of
         microwave radiation is used to detect and locate distant
         objects [syn: {radar}, {microwave radar}, {radio detection
         and ranging}, {radiolocation}]
    

radar \ra"dar\ (r[=a]"d[aum]r), 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?. [acronym]
      [PJC]

   2. The method of detecting objects, finding their distance,
      or determining their speed, by use of a radar[1] device;
      as, modern radar can detect objects as small as raindrops.
      [PJC]
    

92 Moby Thesaurus words for "radar":
      AA radar, AFC, AFC mixer, CRT, CW oscillator, MAD radar, Navaglobe,
      Oboe, TR switch, TR unit, VAR, Volscan, altimeter, amplifier,
      analyzer, astronavigation, automatic electronic navigation,
      automation, avionics, cascade screen, cathode-ray tube,
      celestial navigation, chronometer, coastwise navigation, consolan,
      dead reckoning, demodulator, detector, discriminator,
      early-warning radar, electron microscopy, electron optics,
      electron physics, electronic engineering, electronic navigation,
      electronics, electrophysics, fix, frequency meter,
      gun-directing radar, hard-tube pulser, indicator,
      interception radar, limiter, line of position, local oscillator,
      long-range radar, loran, magnetron, microwave mixer, mixer,
      modulator, navar, navigation, network pulser,
      omnidirectional range, omnirange, oscillator, overlapping,
      panoramic radar, photoelectricity, pilotage, plane sailing,
      point-to-point navigation, potentiometer, pulse generator,
      radar telescope, radio, radio beacon, radio navigation, radionics,
      range-sweep amplifier, range-sweep generator, receiver, screen,
      second detector, sextant, shoran, sofar, sonar,
      square-wave generator, synchronizer, tables, tacan, teleran,
      television, timing unit, tracker, transistor physics, transmitter,
      trigatron, visual-aural range