radar
RAY-dar
/ˈreɪdɑːr/
A system or device that uses radio waves to detect the speed and position of moving vehicles.
In traffic enforcement, radar specifically refers to the handheld or vehicle-mounted guns used by officers to measure speed.
The story behind the word. Coined in 1940 by the United States Navy, RADAR is an acronym for 'RAdio Detection And Ranging'. It was developed as a secret military technology during World War II to detect enemy aircraft before being adapted for civilian traffic control.
Word relationships
- speed gun: Speed gun is a more colloquial term, while radar refers to the specific technology used.
Commonly confused with
- lidar: Radar uses radio waves, while lidar uses pulsed laser light to calculate vehicle speed.
Word family
- radared (verb): To detect or measure speed using radar (informal).
Collocations
- radar gun
- radar detector
- police radar
- radar speed trap
Idioms & expressions
- under the radar
Example sentences
- "The highway patrol officer parked in the median, using a radar gun to catch speeders coming over the hill." A warning about speed traps on highway routes.
Memory hook
R-A-D-A-R is spelled the same backward and forward, just like the radio waves that bounce back to the device. Radio waves bounce back to the radar.
When not to use
Do not confuse 'radar' with 'lidar', which uses laser light instead of radio waves to measure speed, though drivers use 'radar' colloquially for both.
Fun facts
- Because radar is a palindrome, it is one of the few military acronyms that has become a fully integrated lowercase word in everyday language.
Related words
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