n.
- a long, narrow ditch.
▸a ditch of this type dug by troops to provide shelter from enemy fire.
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(also ocean trench)
a long, narrow, deep depression in the ocean bed, typically running parallel to a plate boundary and marking a subduction zone.
v.
- dig a trench or trenches in.
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(trench on/upon)
archaic border closely on; encroach upon.
Etymology
ME (in the senses ‘track cut through a wood’ and ‘sever by cutting’): from OFr. trenche (n.), trenchier (v.), based on L. truncare (see truncate).