Hurrah
late 17th century: alteration of huzza; perhaps originally a sailors' cry when hauling.
wiktionary
Unknown. Possibly adopted from German hurra, itself of uncertain origin, or possibly an alteration of huzzah.
etymonline
hurrah (interj.)
1680s, apparently an alteration of huzza; it is similar to shouts recorded in German, Danish, and Swedish; perhaps it was picked up by the English soldiery during the Thirty Years' War. Hurra was said to be the battle-cry of Prussian soldiers during the War of Liberation (1812-13), "and has since been a favourite cry of soldiers and sailors, and of exultation" [OED]. Hooray is its popular form and is almost as old. Also hurray (1780); hurroo (1824); hoorah (1798). As a verb from 1798. American English hurra's nest "state of confusion" is from 1829.
