High Quality Content by WIKIPEDIA articles! An anti-ballistic missile (ABM) is a missile designed to counter ballistic missiles (a missile for missile defense). A ballistic missile is used to deliver nuclear, chemical, biological or conventional warheads in a ballistic flight trajectory. The term "anti-ballistic missile" describes any antimissile system designed to counter ballistic missiles. However the term is used more commonly for systems designed to counter intercontinental ballistic missiles (ICBMs).