Radar stands for Radio Detection and Ranging. It uses electromagnetic waves to detect objects and determine their range, direction, or speed. The basic parts of a radar system include a transmitter, receiver, antenna, and indicator. The radar equation describes the power returning to the receiving antenna based on factors like the transmitted power, antenna gains, radar cross section of the target, and distance. Different types of radars include pulse, moving target indication, pulse Doppler, and tracking radars. Military radars have advantages like all-weather capability and rapid target detection that make them important for air defense, ground surveillance, and other defense applications.