You can hear it echoing from the hallowed halls of Fort Benning, Ga.'s Infantry Center to the ranges at Fort Lewis, Wash. It is uttered at award ceremonies, bellowed from formations, and repeated before, during and after training missions. You can hear it shouted by Air Force Security Forces, Pararescue, and Combat Controllers. The word is thundered out by Navy SEALs, and by United States Marines (who pronounce it "OohRah!").

So, where did the term originate? The simple answer is that nobody knows, although there are dozens of theories. Heck, nobody can even agree on the correct spelling of this widely used military "word."

No matter how one might spell the word -- with or without a hyphen, a U instead of two Os, and so on -- the word is still an expression of high morale, strength and confidence. And, when powered by an overwhelmingly proud, and usually loud, tone of voice, hooah seems to stomp out any possibility of being bound by the written word.

"It's an affirmation that I fully agree with and support the idea or intent expressed by the person to whom I make that response," said Maj. Gen. F.A. Gorden, Military District of Washington commander. "It applies not only to the letter of what was said, but to the spirit of what was said."

Former Army Chief of Staff Gen. Gordon R. Sullivan has his interpretation. "I don't know how exactly to spell it, but I know what it means," Sullivan said. "It means we have broken the mold. We are battle focused. Hooah says "Look at me. I'm a warrior. I'm ready. Sergeants trained me to standard. I serve America every day, all the way.'"