# Weapon of Mass Destruction **Entity class:** Legal and security concept **Weapon of mass destruction (WMD)** is a defined legal term whose scope depends on the controlling statute. Under 18 U.S.C. §2332a it includes specified destructive devices and weapons involving toxic chemicals, biological agents/toxins/vectors, or dangerous radiation. The systems ontology uses the separate term [[wiki/Mass-Casualty Threat System|mass-casualty threat system]] for broader human–network–platform assemblies. ## Relationships [[wiki/Biological Agent|Biological Agent]] · [[wiki/WMD Delivery System|WMD Delivery System]] · [[wiki/Weapon of Mass Influence|Weapon of Mass Influence]] ## Sources - [18 U.S.C. §2332a — use and definition of weapons of mass destruction](https://uscode.house.gov/view.xhtml?edition=prelim&f=treesort&fq=true&granuleId=USC-prelim-title18-section2332a) **As of:** 2026-09-23