I'd say that the difinition that you cite would be the "dictionary" definition. The political buzzword definition would be just "Nuclear, Biological & Chemical" weapons. At least in the artillery, those were the only projectiles that said, "Illegal WMD ammunition, keep out of reach of the UN, the Geneva Convention, The International Committee of the Red Cross and the U.S. Press (unless it's Fox News because nobody believes Geraldo anyway." ;~D