ypres(n = noun.act) 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; Array
ypres(n = noun.act) battle of ypres, second battle of ypres - 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; Array