Why is the ninth month called September?
1680s, alteration of huzza, similar to shouts recorded in German, Danish, Swedish. Perhaps picked up during Thirty Years' War. Hurra was said to be the battle-cry of Prussian soldiers during the War of Liberation (1812-13). Hooray is its popular form and is almost as old. Also hurray (1780); hurroo (1824); hoorah (1798).