Wa ‧ ter ‧ loo /ˌwɔːtəˈluː◂ $ ˌwɔːtər-, ˌwɑː-/ BrE AmE
1 . the Battle of Waterloo an important battle fought in 1815 near Brussels, Belgium, in which the Duke of Wellington, leading the British and the Prussians, defeated Napoleon and the French. It was Napoleon’s final defeat, and he never regained power after this.
2 . meet your Waterloo to be finally defeated after a long period of success:
Despite widespread unpopularity, the party did not meet its Waterloo until the election of 1997.
3 . one of the main railway stations in London, just south of the River Thames. Trains from Waterloo go to the south and southwest of England.