Weapons plutonium refers to a specific type of plutonium, which is used in nuclear weapons. Synonyms for this term include nuclear weapons-grade plutonium, fissile plutonium, and bomb-grade plutonium. These terms are used interchangeably because they all refer to the same thing - plutonium that is suitable for use in nuclear weapons. The atomic number of plutonium is 94, and it is a highly radioactive element that can be deadly when ingested or inhaled. The use of weapons plutonium is heavily regulated, and many countries have strict laws governing its production, transport, and storage. Despite its lethal properties, weapons plutonium continues to be an important component of nuclear weapons development.