What does radar mean?
Radar is a technology for detecting objects by transmitting radio waves and measuring the signals that reflect back. It can reveal an object's presence and, depending on the system, its distance, direction, and speed. Radar is used for air traffic control, weather forecasting, maritime navigation, military operations, and many industrial and scientific applications. The word also has a useful figurative meaning: when something is “on your radar,” it has entered your awareness or area of attention, even if it is not yet urgent. This figurative use makes radar especially effective in discussion of problems, trends, opportunities, and people whom an organization or individual is watching. Although “radar” sometimes appears in phrases suggesting close attention, the literal technology detects objects through reflected radio waves rather than through ordinary seeing or hearing.
A system that detects objects by sending out radio waves and analyzing reflected signals, often determining distance, direction, or speed.
"The aircraft disappeared from the radar during the storm."
The term can also denote the general technology rather than a particular radar installation.
To monitor, detect, or keep track of something, especially with radar or, figuratively, through continued attention.
"The agency continues to radar the coastline for unusual activity."
The verb sense is uncommon and is more often encountered in figurative expressions than in literal radar use.
The plural is used when referring to multiple radar systems or installations.
"Several radars were installed along the coast."
Radar is an acronym for “radio detection and ranging,” turning invisible radio waves into a map of what lies beyond the horizon.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does radar come from?
The word was formed in the 1940s as an acronym for “radio detection and ranging,” describing the use of radio waves to detect objects and determine their range. Its components—radio, detection, and ranging—reflect the emerging technology of military and civilian radar. Radar developed rapidly during the Second World War and later became common in navigation, meteorology, aviation, and scientific research.
How radar is actually used
The word is standard in technical and general contexts. The figurative sense, especially in the expression “on someone's radar,” is common in informal and professional speech. In British usage, the pronunciation may end with a non-rhotic sound.
Easily confused with radar
Radar uses radio waves and their reflections, whereas sonar uses sound waves and their reflections.