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 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 often does not make this distinction. 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.
Handheld firearms first appeared in China where
gunpowder was first developed. They were
hand cannons (although they were not necessarily fired from the hand, but rather at the end of a handle). By the 14th century, they existed in Europe as well. The first handheld firearms that might better be called "pistols" were made as early as the 15th century, but their creator is unknown.
 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. Previously there had been no such differentiation, and in fact Samuel Colt's original patent was for a "revolving-breech pistol". There is no literal equivalent for "handgun" in the
Romance languages, which continue to use
cognates of the word "pistol".