On Monday, the federal government charged suspected Boston Marathon bomber Dzhokhar Tsarnaev with "unlawfully using and conspiring to use a weapon of mass destruction."

Say what?

For most, the term WMD suggests complex nuclear or chemical weaponry, the sort of devastating arsenal Saddam Hussein supposedly had prior to the U.S-led invasion of Iraq. The biggest weapons Tsarnaev and his brother are accused of using? Pressure cookers full of sharp metal objects.

So how does a souped-up kitchen appliance get roped in with weapons that can cross continents and obliterate entire cities? The answer is the government's very loose definition of what constitutes a WMD.

By law, a WMD can be "any explosive, incendiary, or poison gas," including bombs, grenades, and mines, regardless of their blast potential. Missiles and rocket-propelled explosives also qualify, so long as they meet minimal requirements on the size of their charges.

By that definition, virtually any improvised explosive can be classified as a WMD, which "speak[s] to the definitional absurdity" surrounding those weapons, says Wired's Spencer Ackerman.

"About all that doesn't apply are firearms and pyrotechnics gear," he says. "No one ever said the law had to coincide with military terminology."

So how did we get to the point where firecrackers, if used toward evil ends, could possibly be classified as WMDs?

As Foreign Policy's Timothy Noah notes, the U.S. first used the term "weapons of mass destruction" in the 1940s to describe nuclear warheads. A few years later, the United Nations expanded that definition to include chemical and biological weapons, diluting the term's meaning. That erosion continued over the years such that Tsarnaev's case now "renders entirely meaningless a phrase that was already too crudely propagandistic to warrant much respect," says Noah.

Give me a break. Even granting that the language of the law is not the same as the language of everyday speech, it's ridiculous to call the bombs that went off in Boston "weapons of mass destruction." If any old bomb can be called a WMD, then Saddam most definitely had WMDs before the United States invaded Iraq 10 years ago. And if an IED is a WMD, then Iraq actually ended up with more WMDs after the U.S. invasion than before (and isn't entirely rid of them yet). [Foreign Policy]

But ridiculous or not, the charges against Tsarnaev, which carry a maximum penalty of death or life in prison, fit the letter of the law.