trench

noun
1
a long, deep hole dug in the ground, for example for carrying away water
خندق, آبراه, کانال
2
a long, deep hole dug in the ground in which soldiers can be protected from enemy attacks (for example in northern France and Belgium in the First World War)
سنگر, خندق
life in the trenches
They had not been prepared for the horrors of trench warfare.
3
a long, deep, narrow hole in the ocean floor
شکاف دریایی, دره زیرآبی