Missile defense refers to a system designed to detect, track, and intercept incoming missiles before they can reach their intended targets. These systems use various technologies, including radar and interceptor missiles, to neutralize threats from ballistic missiles, cruise missiles, and other aerial attacks. Countries like the United States and Israel have developed advanced missile defense systems, such as the Patriot and Iron Dome, to protect their populations and critical infrastructure. These systems aim to enhance national security by providing a protective shield against potential missile attacks from adversaries.