The flint is held in a clamp at the end of a bent lever called the cock. Upon pulling the trigger, this moves forward under the pressure of a strong spring and strikes a curved plate of hardened steel (called simply the steel, or in 17th century English dialect the frizzen) to produce a shower of sparks (actually white-hot steel shavings). These fall into a flash pan holding priming powder. The flash from the pan travels through the touch hole to cause the main charge of gunpowder to deflagrate.
The snaphance first appeared in the late 1550s as a development of the earlier snaplock. The main improvement was that the pan-cover opened automatically (to keep the priming dry until the exact moment of firing), as in the wheel-lock. (The snaplock had a manually operated pan cover similar to that of the matchlock. Some definitions class the snaphaunce as a sub-type of snaplock.) Also like the wheel-lock, the snaphance used a lateral sear mechanism to connect trigger to cock. Later models had a variety of safety mechanisms to prevent accidental discharge of the gun.
The snaphance was used from the late 1550s until modern times (in North African guns), but by about 1680 it was out of fashion everywhere except Northern Italy where it persisted until the 1750s. In Europe, and especially France, the snaphance was replaced by the flintlock with its combined steel/pan cover starting from about 1620. In England, a hybrid mechanism called the English Lock replaced the snaphance from the same date. Both the flintlock and the English lock were cheaper and less complex than the snaphance.
The origin of the name snaphance is thought to come from the Dutch language "Snap Haan" or German language "Schnapphahn"—both of which roughly mean "hen peck", and could relate to the shape of the mechanism and its downward-darting action (and would also explain the name "cock" for the beak-shaped mechanism which holds the flint). A more fanciful explanation relates to the use of this type of gun by chicken thieves, who would be given away by the sight and smell of a burning match if they had used the earlier matchlock gun in their nocturnal depredations. The German word Schnapphahn had however since moved away from the earlier definitions and has traditionally referred to a mounted highwayman, who would have been likely to use a firearm of that nature. The French chenapan also changed its meaning in the seventeenth century to define a rogue or scoundrel.