[ABM] Anti Ballistic Missile, the one and possabley only way of stopping any nuclear weapon

[ATOMIC REASEARCH] The first stage into nuclear weapons

[IRBM] Intermediate Range Ballistic Missile, a short range nuclear rocket

[ICBM] Intercontinental Ballistic Missile, a very far range nuclear weapon

[THERMONUCLEAR RESEARCH] A thermo nuclear bomb is way stronger than an atomic bomb and way bigger