A nuclear weapon is a weapon of mass destruction that uses the energy released from a nuclear reaction to cause an explosion. The most common type of nuclear weapon is a nuclear bomb, which is a device that uses either fission or fusion to create a powerful blast. DETERRENT, a nine-letter word, is a term used to describe a nuclear weapon's ability to deter an enemy from attacking by threatening massive retaliation. The two most common types of nuclear bombs are the atomic bomb (abomb) and the hydrogen bomb (hbomb). Atomic bombs use fission to create a powerful blast, while hydrogen bombs use fusion to create an even more powerful blast.