The word gun may come from a giant crossbow named Lady Gunilda
In the fourteenth century Windsor Castle housed an enormous mechanical bolt-thrower nicknamed Domina Gunilda. Her name, likely from the Old Norse Gunnhildr, built from two words for battle and often shortened to Gunna, is the leading explanation for the English word gun, which first shows up as gonne in a Latin document around 1339.
Broadly, a gun is any device that pushes a projectile out using pressure or explosive force. Usually the pressure comes from gas trapped in a barrel, generated by burning propellant in firearms and cannon or by mechanical compression in air guns. Projectiles can be solid, liquid as in water cannon, or tethered, as with harpoon guns and Tasers. Experimental railguns and coilguns swap gas for electromagnetic fields. Guns were designed for war first and adopted for hunting later.
Historians argue over what counts as a true gun. Tonio Andrade and Joseph Needham both insist the projectile must fill, or occlude, the barrel; Needham added that a real gun also needs a metal barrel and high-nitrate gunpowder. By that standard the Chinese fire lance, a bamboo tube of powder tied to a spear, is only a proto-gun. Painted on silk in the mid-tenth century and recorded at the siege of De'an in 1132, it was later packed with porcelain shards or iron pellets but reached only about 3 metres. Needham's eruptor, part fire lance and part gun, was another proto-gun.
True guns emerged in China in the late 1200s, roughly three centuries after the fire lance, and spread across Eurasia during the fourteenth century. Historians apply the word retroactively to early pieces such as the Heilongjiang hand cannon of 1288 and a vase-shaped European cannon of 1326. By the 1480s guns reached a classic form, longer, lighter and more accurate than designs of just 30 years earlier, and it scarcely changed until the mid-eighteenth century.
Medieval vocabulary was colourful. Italians spoke of schioppi, thunderers, and the Dutch donrebusse, thunder gun, became the English blunderbuss. Gunners were called gonners, and the phrase hand gun appeared in 1373, originally referring to the weapon's handle.
Source: Gun
