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.