A hypersonic weapon is a weapon capable of travelling at hypersonic speed, defined as between 5 and 25 times the speed of sound or about 1 to 5 miles per second.

Missile defense is a system, weapon, or technology involved in the detection, tracking, interception, and also the destruction of attacking missiles. Conceived as a defense against nuclear-armed intercontinental ballistic missiles (ICBMs), its application has broadened to include shorter-ranged non-nuclear tactical and theater missiles.