(uncountable) A method of detecting distant objects and determining their position, velocity, or other characteristics by analysis of sent radio waves (usually microwaves) reflected from their surfaces

(countable) A type of system using such a method, differentiated by platform, configuration, frequency, power, and other technical attributes.

(countable) An installation of such a system or of the transmitting and receiving apparatus.

(countable, figurative) A superior ability to detect something.

To scan with radar, or as if with radar.