(trench) noun
1. A long narrow excavation in the ground; ditch.
2. A long irregular ditch, lined with a parapet of the excavated earth, to protect troops: often with a descriptive word: communication, reserve, shelter, or supply trench.
—v.t.
1. To dig a trench or trenches in.
2. Mil. To fortify with trenches; construct trenches against.
3. To cut deep furrows in; ditch.
4. To confine in a trench, as water; entrench.
—v.i.
5. To cut or dig trenches.
6. To cut; carve.
7. To encroach. [<OF trenche a cutting, gash <trenchier cut, ult. <L truncare lop off <truncus a tree trunk]

(trench), Richard Chenevix,
1807–86, English prelate, poet, and philologist.