Wiktionary
n. Any human-made weapon causing indiscriminate large-scale death or destruction, especially a biological weapon, chemical weapon, nuclear weapon or radiological weapon.
WordNet
n. a weapon that kills or injures civilian as well as military personnel (nuclear and chemical and biological weapons) [syn: WMD, W.M.D.]
Wikipedia
A weapon of mass destruction (WMD or WoMD) is a nuclear, radiological, chemical, biological or other weapon that can kill and bring significant harm to a large number of humans or cause great damage to human-made structures (e.g. buildings), natural structures (e.g. mountains), or the biosphere. The scope and application of the term has evolved and been disputed, often signifying more politically than technically. Originally coined in reference to aerial bombing with chemical explosives, since World War II it has come to refer to large-scale weaponry of other technologies, such as chemical, biological, radiological, or nuclear.
Usage examples of "weapon of mass destruction".
The results to Brazil are as if a weapon of mass destruction had been unleashed upon us.
I guess the Nasty Nine had roused Dtang's dreaded bowel, and he was going to use it as a weapon of mass destruction.
Without recognizing it, humankind created a weapon of mass destruction -- one that only became apparent after machines took over every aspect of their lives.