Radar Cross Section (RCS) is a measure of how detectable an object is by radar. It quantifies the amount of radar energy that is reflected back to the radar source when it hits an object. The larger the RCS, the easier it is for radar systems to detect the object. RCS is influenced by several factors, including the object's size, shape, and material. For example, stealth technology in military aircraft, like the F-22 Raptor, is designed to minimize RCS, making them harder to detect by radar systems.