From Longman Dictionary of Contemporary Englishradarra‧dar /ˈreɪdɑː $ -ɑːr/ ●○○ noun 1 TMTT[countable, uncountable] a piece of equipment that uses radio waves to find the position of things and watch their movement → sonar The coastline can now be monitored by radar. We could see the plane quite clearly on the radar screen.2 → on somebody's/the radar (screen)3 → fly/slip under somebody's/the radar
Examples from the Corpus
radar• And the overlap could be especially acute in this deal, because both companies are major producers of missiles and radar.• The idea behind radar was to send out radio waves and listen for echoes from enemy craft.• Enemy radar must have detected our approach.• Then, the race was for radar.• The aircraft had begun its descent to Houston Intercontinental Airport when it disappeared from radar screens.• Nor are the skies above frequented by commercial airlines, which eliminates interfering radar signals.• Rough seas reflect radar signals, producing false echoes which can blind an old radar such as the Type 992.• The same radar data that permit determination of the rotation speed of Venus also permit us to prepare maps of its surface.From Longman Business Dictionaryradarra‧dar /ˈreɪdɑ-dɑːr/ noun [uncountable]1be off/below the radar (screen) used when saying that people do not know about or are not thinking about something, especially something that will later become importantMany of these technologies were below the radar of the mainstream business press.HIV/AIDS has fallen off our radar screens in recent years.2be on the radar (screen) used when saying that people know about or are thinking about something, especially something that will later become importantStem cell research and biotech in general are on the radar screen of venture capitalists nationwide.Origin radar (1900-2000) radio detection and ranging 