Radar cross section (RCS) is used to characterize the scattering properties of a radar target. This target could be an automobile or a warplane. Usually it is measured in meters squared (m2).

For comparison, a typical automobile will have a 100 m2 RCS at a certain frequency and an advanced technical fighter jet will have about 0.000001 m2 RCS at the same frequency.

Facts shamelessly pulled from Constantine Balanis' textbook Antenna Theory Analysis and Design.