(geology, oceanography) A hemispheric-scale long but narrow topographic depression of the seabed.

(archaeology) A triangle-shaped cut in a tell, used to see how many levels there are or to find information about each separate settlement.

A military-style raincoat with a belt and deep pockets and often epaulettes.

(medicine) An acute infectious disease, caused by the microorganism Rickettsia quintana (now Bartonella quintana) and transmitted by the louse Pediculus humanus, that affected very many soldiers during World War I.

(oceanography) A submarine trench in the North Pacific Ocean, noted for having the deepest known point on Earth.

(uncountable) Warfare in which opposing sides occupy trenches and repeatedly fire at one another; usually involving high casualty rates over a long period of time.

an attitude towards differences of opinion, where oppositional stand-off or conflict is preferred over debate and compromise.

plural of trench mentality

A deep-sea trench in the Pacific Ocean to east of the Philippines.

A plough for turning up the land more deeply than usual.