A pistol is a type of handgun. In some usage, the term "pistol" refers to a subset of handguns: those with a chamber integral with the barrel. In other usage, the term is interchangeable with "handgun".
Some handgun experts and dictionaries make a technical distinction that views pistols as a subset of handguns; others use the terms interchangeably. Sometimes in usage, the term "pistol" refers to a handgun having one chamber integral with the barrel, making pistols distinct from the other main type of handgun, the revolver, which has a revolving cylinder containing multiple chambers. But UK/rest of Commonwealth usage does not always make this distinction, particularly when the terms are used by the military. For example, the official designation of the Webley Mk VI revolver was "Pistol, Revolver, Webley, No. 1 Mk VI". In contrast to Merriam-Webster the Oxford English Dictionary (a descriptive dictionary) describes 'pistol' as a small firearm to be used in one hand and the usage of "revolver" as being a type of handgun and gives its original form as "revolving pistol"
The pistol originates in the 16th century, when early handguns were produced in Europe. The English word was introduced in ca. 1570 from the Middle French pistolet (ca. 1550).
The etymology of the French word pistolet is disputed. It may be from a Czech word for early hand cannons, píšťala "whistle", or alternatively from Italian pistolese, after Pistoia, a city renowned for Renaissance-era gunsmithing, where hand-held guns (designed to be fired from horseback) were first produced in the 1540s.
The first suggestion derives the word from Czech píšťala, a type of hand-cannon used in the Hussite Wars during the 1420s. The Czech word was adopted in German as pitschale, pitschole, petsole, and variants.
The second suggestion is less likely; the use of the word as a designation of a gun is not documented before 1605 in Italy, long after it was used in French and German. The Czech word is well documented since the Hussite wars in 1420s.