Second Battle of Ypres

The Second Battle of Ypres was the first time Germany used poison gas on a large scale on the Western Front in World War I and the first time a former colonial force (Canadians) pushed back a major European power (Germans) on European soil, which occurred in the battle of St. Julien-Kitcheners' Wood.
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Noun
1. battle in World War I (1915); Germans wanted to try chlorine (a toxic yellow gas) as a weapon and succeeded in taking considerable territory from the Allied salient
(synonym) Ypres, battle of Ypres
(hypernym) pitched battle
(part-holonym) World War I, World War 1, Great War, First World War, War to End War
(classification) Belgium, Kingdom of Belgium, Belgique