a long narrow excavation in the ground, esp one dug for drainage or to allow underground pipes, cables, etc to be laid

a deep ditch, often one of a series, used for military defence, usu with the excavated earth banked up in front for protection

a long, narrow, and usu steep-sided depression in the ocean floor

to dig a trench or trenches in (a piece of ground)

to protect (a military position or its troops) by digging a trench or trenches

to dig or plough (a field) deeply; esp to turn over (soil) three or more times the depth of a spade

archaic (+ on/upon) to encroach on something or come close to it

trenching on other domains which were more vital — Winston Churchill