noun
radar
RAY-dah
noun
1
A system that detects and tracks objects by sending out radio waves and analyzing the signals that bounce back.
"Air traffic controllers use radar to track planes approaching the airport."
2
An informal, figurative sense: someone's awareness or instinct for noticing something.
"His radar for bad business deals kicked in immediately."
"The new hire is talented but flew under management's radar for months."
How to Use Radar
Learner’s notesIn plain EnglishA detection system using radio waves, or informally, a sharp instinct for spotting something.
Common mistake
Since "radar" began life as an acronym, it doesn't need capital letters in modern writing.
Common pairings
on the radar
under the radar
radar screen
fly under the radar
Word Forms
radared past tense, radars plural, radars singular
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Air traffic controllers use _____ to track planes approaching the airport.
Etymology
Originally an acronym for "radio detection and ranging", coined by US Navy officers in 1940; it later became an ordinary word in its own right.