trench warfare
From Longman Dictionary of Contemporary EnglishRelated topics: Militarytrench warfareˌtrench ˈwarfare noun [uncountable] PMa method of fighting in which soldiers from opposing armies are in trenches facing each otherExamples from the Corpustrench warfare• Yet to continue trench warfare as before would be a mistake.• Lastly, trench warfare is a policy Mr Yeltsin has pursued with some success for much of the past 12 months.• The little-noticed trench warfare over Senate confirmation of presidential appointees is nothing new.• The musical evokes the courage and humour of the troops amidst the horror of trench warfare.