an area in northern France and Belgium where many battles of World War I were fought. The armies of theAllies (=Britain, France etc) and of Germany were based in trenches (=long, deep holes in the ground) and suffered terrible conditions and great loss of life.
Definition from the Longman Dictionary of Contemporary English Advanced Learner's Dictionary.
Dictionary pictures of the day
Do you know what each of these is called?
Click on any of the pictures above to find out what it is called.