(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.

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

(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.

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

A medical condition which can affect the feet when they are constantly cold and wet, similar to frostbite.

(idiomatic, medicine) Acute necrotizing ulcerative gingivitis, a severe bacterial infection of the gums, typically characterized by inflammation, bleeding, deep ulceration, necrotized tissue, pain, fever, enlarged lymph nodes, fatigue, and halitosis.

plural of trench cut

plural of trench coat

A large heavy gauge metal plate used to span holes in streets to allow vehicular traffic across the gap.