That word is "hooah." Pronounced HOO-ah.
It's not just in Iraq. At U.S. bases around the world, hooah seems an inseparable element of Army life. Just don't try to define it. And definitely don't try to figure out where it comes from.
Hooah is a catchall phrase that will get you out of any situation, particularly when receiving a scolding from a higher-ranking officer. "You use it when you've got a flame on your butt and you're just trying to extinguish it," said Capt. Brian Buckner, 30, of Sumter, S.C.
For the different branches of the military, each vastly competitive with and jealous of its distinctions from one another, hooah has become something of a sore point. Marines and sailors have their own saying, more of a "hoo-RAH" or a "hoo-yah," which they claim is entirely separate in origin.
As with any good word, the origins of hooah are highly disputed. Some claim it derives from the military acronym HUA -- Heard, Understood, Acknowledged.
Another tale: When Army Rangers landed at Omaha Beach on D-Day in 1944, a sergeant ordered them to scale the cliffs looming above them and neutralize the German pillboxes perched on top. One soldier, aghast at the idea, responded, "Who, us?"
Then there's the theory that hooah comes from hurrah and hooray, themselves believed to be bastardizations of the sailor's cry "huzzah," which dates back to the 16th century.
More to this article at http://story.theusnews.com/p.x/ct/9/cid/187cf2a69985adcf/id/b19ea6cdd645b00d/
I like 'Who, us?' :) but it's probably just another military acronoym like Heard, Understood, Acknowledged... or Roger that...