Pistol

A pistol is a type of 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/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"

https://en.wikipedia.org/wiki/Pistol