Weapons of Mass Destruction (WMD) refer to a category of weapons that can cause significant harm to large numbers of people and extensive damage to infrastructure. This category includes three main types: nuclear weapons, chemical weapons, and biological weapons. Each type has the potential to inflict mass casualties and disrupt societies. WMD are often associated with international security concerns, as their use can lead to devastating consequences. Countries and organizations monitor the proliferation of these weapons to prevent their spread and ensure global safety. Treaties like the Nuclear Non-Proliferation Treaty aim to limit the development and stockpiling of WMD.