variants often Waterloo
plural waterloos
: a decisive or final defeat or setback
a political waterloo

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The Battle of Waterloo, which occurred on June 18, 1815, has given its name to the very notion of final defeat. Why? Maybe because it ended one of the most spectacular military careers in history (Napoleon's), as well as 23 years of recurrent conflict between France and the rest of Europe. In addition, it was Napoleon's second "final defeat." He was defeated and exiled in 1814, but he escaped his confinement, returned to France, and was restored to power for three months before meeting defeat at the hands of the forces allied under the Duke of Wellington near the Belgian village of Waterloo. The word waterloo first appeared in casual use the following year, 1816.

Word History

Etymology

Waterloo, Belgium, scene of Napoleon's defeat in 1815

First Known Use

1816, in the meaning defined above

Time Traveler
The first known use of waterloo was in 1816

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Cite this Entry

“Waterloo.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/waterloo. Accessed 30 Jul. 2026.

Geographical Definition

Waterloo

geographical name

Wa·​ter·​loo ˌwȯ-tər-ˈlü How to pronounce Waterloo (audio)
ˌwä-;
ˈwȯ-tər-ˌlü
ˈwä-
1
city in northeast central Iowa northwest of Cedar Rapids population 68,406
2
town in central Belgium south of Brussels population 28,898

Note: In June 1815, a battle near Waterloo resulted in the decisive defeat of French Emperor Napoléon I.

3
city in southeastern Ontario, Canada, west of Kitchener population 98,780

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