n a ditch dug as a fortification having a parapet of the excavated earth
n a long steep-sided depression in the ocean floor
n any long ditch cut in the ground
v impinge or infringe upon
v fortify by surrounding with trenches
v cut or carve deeply into
v set, plant, or bury in a trench
v cut a trench in, as for drainage
v dig a trench or trenches