Flintlock mechanism in the context of Thomas Ketland

Flintlock is a general term for any firearm that uses a flint-striking ignition mechanism, the first of which appeared in Western Europe in the early 16th century. The term may also apply to a particular form of the mechanism itself, also known as the true flintlock, that was introduced in the early 17th century, and gradually replaced earlier firearm-ignition technologies, such as the matchlock, the wheellock, and the earlier flintlock mechanisms such as the snaplock and snaphaunce.

The true flintlock continued to be in common use for over two centuries, replaced by percussion cap and, later, the cartridge-based systems in the early-to-mid 19th century. Although long superseded by modern firearms, flintlock weapons enjoy continuing popularity with black-powder shooting enthusiasts.

A touch hole, also known as a cannon vent, is a small hole at the rear (breech) portion of the barrel of a muzzleloading gun or cannon. The hole provides external access of an ignition spark into the breech chamber of the barrel (where the combustion of the propellant occurs), either with a slow match (matchlock), a linstock or a flash pan ignited by some type of pyrite- (wheellock) or flint-based gunlock (snaplock, snaphaunce, and flintlock), which will initiate the combustion of the main gunpowder charge. Without a touch hole, it would be nearly impossible to ignite the powder because the only otherwise access into the barrel is from the front via the muzzle, which is obturated by the projectile.

In the later caplock firearms, the ignition sparks are generated by a shock-sensitive percussion cap placed over a conical "nipple", which has a hollow conduit known as the flash channel, that leads into the barrel and serves the same function as the touch hole.

A snaplock / snaphaunce is a type of lock for firing a gun or is a gun fired by such a lock.

A snaplock ignites the (usually muzzle-loading) weapon's propellant by means of sparks produced when a spring-powered cock strikes a flint down on to a piece of hardened steel. The snaplock is therefore similar to the snaphance (sometimes classed as an advanced type of snaplock) and the later flintlock (see below).

A snaphance or snaphaunce is a type of firearm lock in which a flint struck against a striker plate above a steel pan ignites the priming powder which fires the gun. It is the mechanical progression of the wheellock firing mechanism, and along with the miquelet lock and doglock are predecessors of the flintlock mechanism.

The name is Dutch in origin but the mechanism cannot be attributed to the Netherlands with certainty.

A doglock is a type of lock for firearms that preceded the 'true' flintlock in rifles, muskets, and pistols in the 17th century. Commonly used throughout Europe in the late seventeenth century, it gained popular favor in the British and Dutch military. A doglock carbine was the principal weapon of the harquebusier, the most numerous type of cavalry in the armies of the Thirty Years' War and English Civil War era. Like the snaphance, it was largely supplanted by the flintlock.

Much like the later flintlock devices, it contained the flint, frizzen, and pan, yet had an external catch as a half-cock safety, known as the "dog". This type of lock had no internal, half-cock loading position as the later flintlock mechanism contained. To load a firearm with a dog lock, the cock was secured with the external dog, preventing it from moving forward to strike the frizzen and begin the firing sequence. The user could then safely load the musket or pistol. To fire, the cock was moved to the full-cock position, which caused the dog to fall backward and no longer prevent the lock from firing. A pull of the trigger would then fire the piece. This fell out of favor with the British before 1720. Later flintlocks would contain no such catch, as the half-cock position had been created with the internal parts of the lock.