The crossword solution for the term ARM is BRAS, which is an acronym for the Ballistic Rocket Artillery System. This system is a multiple rocket launcher developed by the Soviet Union during the Cold War. It was designed to launch rockets with a range of up to 70 kilometers and could be used to deliver high explosive, incendiary, or chemical warheads. The BRAS system was used extensively during the Soviet-Afghan War and is still in use today by some countries.