Defining "enormity"

I was an English major in college, and thus the language has always held a special fascination for me. Recently a friend pointed out in his blog an error made by Senator Obama during a Fourth of July speech, during which he used the phrase "the enormity of the American accomplishment."

In conventional usage, "enormity" is used to mean "wickedness" "atrociousness" or an outrageous offensee. One might speak of the "enormity of Voldemort's deeds," but not the enormity of American accomplishments, which should be described as "enormousness" or "immensity."

The word itself derives from Latin e + norm, indicating something out of the ordinary. The dictionaries tend to give the first definition as implying evil, then offer a second definition suggesting greatness of size or scope ("The enormity of such an act of generosity is staggering" - Random House).

Merriam Webster online has the longest discussion of the word:

1: an outrageous, improper, vicious, or immoral act enormities of state power — Susan Sontag> enormities too juvenile to mention — Richard Freedman>
2: the quality or state of being immoderate, monstrous, or outrageous; especially : great wickedness enormity of the crimes committed during the Third Reich — G. A. Craig>
3: the quality or state of being huge : immensity enormity of the universe>
4: a quality of momentous importance or impact enormity of the decision>

usage Enormity, some people insist, is improperly used to denote large size. They insist on enormousness for this meaning, and would limit enormity to the meaning “great wickedness.” Those who urge such a limitation may not recognize the subtlety with which enormity is actually used. It regularly denotes a considerable departure from the expected or normal enormity of their situation burst upon them. “How did the fire start?” — John Steinbeck>. When used to denote large size, either literal or figurative, it usually suggests something so large as to seem overwhelming enormity of the desert or the sight of a tiny flower — Paul Theroux> enormity of the task of teachers in slum schools — J. B. Conant> and may even be used to suggest both great size and deviation from morality enormity of existing stockpiles of atomic weapons — New Republic>. It can also emphasize the momentousness of what has happened enormity of the Russian Revolution — George Steiner> or of its consequences enormity of the misfortune — E. L. Doctorow>.

All in all, one would have to say Senator Obama chose an unfortunate turn of phrase for his speech. He perhaps "misunderestimated" the complexity of the word.