| 
 third battle of Ypres
 
 
 
       
        
         | 1. | (noun) 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 |  
	 |  | Synonyms: Ypres, battle of Ypres |  
	 |  | Related Words: pitched battle |  | 
 |  |