ENGLISH
REFERENCE

radar

n. · v.
US //ˈɹeɪˌdɑɹ// UK //ɹˈeɪdɑː// radar
  1. 1 detection system (n.)
    B1 Intermediate Science

    a system that uses radio waves to find where objects are and how fast they are moving.

    a method or device for detecting distant objects and determining their position or velocity by analysing reflected radio waves.

    Example

    The ship's radar showed another vessel approaching through the thick fog.

    Example

    Air traffic controllers rely on sophisticated primary radar to maintain safe distances between aircraft during peak travel periods at the international airport.

    Usage

    Often used as an uncountable noun when referring to the technology, or countable when referring to the specific device.
  2. 2 awareness or attention (n.)
    B2 Upper Intermediate Informal

    your ability to notice things or the attention people pay to something.

    a figurative capacity for detection, awareness, or social intuition; often used in the phrase 'on the radar' or 'under the radar'.

    Example

    The new technology wasn't even on my radar until you mentioned it.

    Example

    The small startup managed to stay under the radar for two years, developing its product in secret before a major public launch.

    Teacher's tip

    Commonly used in business and social contexts to describe whether something is being considered or noticed.
  3. 3 to scan (v.)
    C1 Advanced Technical Technical

    to check or track something using a radar device.

    to use a radar apparatus to scan or monitor a person, object, or area.

    Example

    The police radared the cars as they drove past the school zone.

    Example

    Coastal patrol units radared the horizon throughout the night to intercept any unidentified vessels entering territorial waters.

    Usage

    This transitive verb use is less common in general conversation than the noun form.
Word family
  • Nounradar
  • NounSSR
Idioms2 entries

Last updated June 19, 2026