coutelace

Old French coutel derived from Latin cultellus, a diminutive of culter — a knife or plowshare blade. Coutelace (later coutelas) was a large, heavy knife — not yet the naval sword. The word entered English as 'curtle-ax' in the 16th century before settling as cutlass by the 17th. The weapon was essentially a cleaver: broad-bladed, single-edged, curved slightly at the tip, designed for heavy cutting rather than precise thrusting.

The cutlass became the standard naval sidearm from the 17th through the early 20th century. Its virtues were perfectly suited to shipboard fighting: short enough to swing in tight spaces below decks, sturdy enough to hack through rigging, and simple enough that an untrained sailor could use it effectively. The boarding actions of the age of sail — climbing up the side of an enemy vessel and fighting hand to hand — required exactly this weapon.

Pirates in the popular imagination carry cutlasses — from Robert Louis Stevenson's Treasure Island (1883) to every subsequent pirate film. The reality was accurate: 17th and 18th century Caribbean pirates did use cutlasses, as did the naval forces hunting them. The Royal Navy issued cutlasses as standard equipment from the 1800s until they were formally declared obsolete in the Royal Navy in 1936.

The US Marine Corps issued a model 1917 cutlass as late as World War I. The weapon that outlasted its era was finally retired in the interwar period, a century after it had ceased to be tactically relevant. Old French coutelace, the large knife, lasted in naval service for three hundred years.