The next development in handgun history after a practical revolver was the development of the semi-automatic pistol, which uses the energy of one shot to reload the next.
Typically recoil energy from a fired round is mechanically harnessed; however, pistols chambered for more powerful cartridges may be gas operated (e.g., Desert Eagle), or for less powerful cartridges, blowback.
Revolvers feed ammunition via the rotation of a cartridge-filled cylinder, in which each cartridge is contained in its own ignition chamber, and is sequentially brought into alignment with the firearms barrel by an indexing mechanism linked to the firearms trigger (double-action) or its hammer (single-action).
These nominally cylindrical chambers, usually numbering between five and ten depending on the size of the revolver and the size of the cartridge being fired, are bored through the cylinder so that their axes are parallel to the cylinder's axis of rotation; thus, as the cylinder rotates, the chambers revolve about the cylinder's axis.
An example of a single-shot pistol is the flare gun.
Although not intended to be a weapon, many variants have been made (See Flare gun).
Although handgun use often includes bracing with a second hand, the essential distinguishing characteristic of a handgun is its facility for one-handed operation.
The word "pistol" is often synonymous with the word "handgun".
By the 18th century, the term came to be used often to refer to handheld firearms.
Practical revolver designs appeared in the 19th century, but it was not until the mid-twentieth century that the (sometimes-observed) differentiation in usage of the words "pistol" and "revolver" evolved among some speakers and the use of "handgun" became prevalent.
Some handgun experts make a technical distinction that views pistols as a subset of handguns.