*zap*
WKR
Technically speaking, the term "pistol" is a hypernym generally referring to a handgun and predates the existence of the type of guns to which it now applied as a specific term, that is: in colloquial usage it is used as a hyponym to specifically describe pistols with a single integral chamber within its barrel. The American Webster's Dictionary defines it as "a handgun whose chamber is integral with the barrel". This makes it distinct from the other types of handgun, such as the revolver.