A motivational cry used by the United States Marine Corps. Sometimes also used as a general response to an order or question. Recon Marines in Korea (1953), traveling by submarine, often heard the dive klaxon which sounded like "Aarrugah." These Marines began using the word as a motivational tool, but it was too long and slowly became modified into what it is today. It was popularized during the 80s and 90s.
"Get some!"
::Marine climbs rope at the end of the obstacle course and slaps the wooden beam at the top, yelling "Oorah!" ::
"Son, you good to go?"
"Oorah, Sir!"
"Grab that pack!"
"Oorah, Sir!"
by USMC Officer Candidate February 26, 2005
Marine Corps response in the affirmative and as a cheer and to signify that a Marine is ready for action.

Started with Marine Amphibious units during the Korean War in 1953. Many Marines had to be delivered to shore by means of submarine. On US Submarines the klaxon alarm sounds when the vessel is about to dive with its classic "Aoogah" sound. When Marines on the submarine heard this distinctive sound it usually meant that they were about to go into battle on shore very soon. It soon became shortened to "Oorah" and signified that a Marine was battle-ready.
Are we going to accomplish this mission? Oorah, Sir!
by JJNYC November 18, 2007
I've heard it said that "Oorah" is derived from the Turkish word "To Kill", and was picked up and adopted by United States Marines during the Korean war. Today it's used as an all-purpose grunt of affirmation, much like the Army's "Hooah", or the Navy SEAL's "Hooyah".
by Herb October 27, 2003
A motivational word used by Marines (usually only 'boots' still use it... 'salts' won't.) It was started by Marines in World War 1 as they came out of the trenches. By the end of the war, when the Germans heard "Ooh-Rah!", they knew the {Marines were assaulting. Because the Marines were so vicious, the Krauts thought it sounded like "Teufelhunden" (German word meaning the "Devil's Dogs"). This is also why the Marines are called 'Devil Dogs'.
C.O. - Are we good to go?
Pvt. - Oorah, sir!
by ks4714 May 10, 2006
The answer to every question posed to a United States Marine. Requires very little intelligence to use.

Can also be used to replace pretty much every word ever.
by stupid_jarhead November 30, 2006
Expression from non-NCO rates (E-1 to E-3) usually followed by fucking with by Corporals and Sergeants.
Boot Private - "Oorah Sergeant" Salty Sergeant - "Push"
by JeremyWolf September 23, 2006
Freely used...Outburst...Excitement.

Of Military origin.
Ooorah! Did you see that headshot?! I pwned his ass!
by Mandy October 2, 2003