Chemical weapon and Weapon of mass destruction

Chemical weapon noun - Chemical substances that can be delivered using munitions and dispersal devices to cause death or severe harm to people and animals and plants.

Weapon of mass destruction and chemical weapon are semantically related. In some cases you can use "Weapon of mass destruction" instead a noun phrase "Chemical weapon".

Weapon of mass destruction noun - A weapon that kills or injures civilian as well as military personnel (nuclear and chemical and biological weapons).

Chemical weapon and weapon of mass destruction are semantically related. Sometimes you can replace phrase "Chemical weapon" with "Weapon of mass destruction", this phrases are similar.