- Ypres, battle of Ypres, third battle of Ypres - battle in World War I (1917); an Allied offensive which eventually failed because tanks bogged down in the waterlogged soil of Flanders; Germans introduced mustard gas which interfered with the Allied artillery
--1 is a kind of pitched battle
--1 is a part ofWorld War I, World War 1, Great War, First World War, War to End War