A knife, typically with a double-edged blade and a knuckleduster on the handle, used for hand-to-hand fighting in trenches, as on a trench raid; (later more generally) any combat knife of a similar design.
Origin
Late 19th century; earliest use found in Weekly News & Courier (Charleston, South Carolina).
Definition of trench knife in US English:
trench knife
noun
A knife, typically with a double-edged blade and a knuckleduster on the handle, used for hand-to-hand fighting in trenches, as on a trench raid; (later more generally) any combat knife of a similar design.
Origin
Late 19th century; earliest use found in Weekly News & Courier (Charleston, South Carolina).