"Multiple senses of the word "pistol"

The word "pistol" is often synonymous with the word "handgun". Some handgun experts make a technical distinction that views pistols as a subset of handguns. In American usage, the term "pistol" refers to a handgun whose chamber is integral with the barrel, making pistols distinct from the other main type of handgun, the revolver, which has a revolving cylinder containing multiple chambers. However, Commonwealth usage makes no distinction at a technical level—"pistol" may refer to revolvers, semi-automatics, or muzzle-loading/cap-&-ball handguns. For example, the official designation of the Webley Mk VI was "Pistol, Revolver, Webley No. 1 Mk VI", and the designation "Pistol No. 2 Mk I" was used to refer to both the Enfield Revolver and the later Browning Hi-Power semi-automatic.[1],[2],[3],[4]

The first pistols were made as early as the 15th century, however the creator is unknown[5]. By the 18th century, the term came to be used often to refer to handheld firearms. Practical revolver designs appeared in the 19th century, and it was in that century that the (sometimes-observed) technical differentiation in usage of the words "pistol" and "revolver" developed.