ETYM French bayonnette, baďonnette; -- so called, it is said, because the first bayonets were made at Bayonne.
A knife that can be fixed to the end of a rifle and used as a weapon.
Short sword attached to the muzzle of a firearm. The bayonet was placed inside the barrel of the muzzleloading muskets of the late 17th century. The sock or ring bayonet, invented 1700, allowed a weapon to be fired without interruption, leading to the demise of the pike.
Since the 1700s, bayonets have evolved into a variety of types. During World War I, the French used a long needle bayonet, the British a sword bayonet, while the Germans adopted a “pioneer” bayonet with the rear edge formed into a saw. As armies have become more mechanized, bayonets have tended to decrease in length.
Although many military leaders have advocated the use of the bayonet, in practice it has been rarely used. For example, at Inkerman during the Crimean War 1854, only 6% of casualties were attributed to the bayonet. In World War I, the “Spirit of the Bayonet” was fostered by instructors, but was little used in real life: of the 13,691 men of the American Expeditionary Force killed in the war, only 5 died from bayonet wounds. However, the morale effects associated with the fixing of bayonets have generally been considered to outweigh their disadvantages, which include restriction of movement and lack of real utility.

To stab or kill someone with a bayonet.