In American English, a pocket pistol is any small, pocket-sized semi-automatic pistol, and is suitable for concealed carry in a pocket or a similar small space.
.25 ACP FN Baby Browning
Original Remington Model 95 derringer
Nineteenth Century Remington Vest-Pocket Pistol No. 1, .22 caliber, on display at the Cody Firearms Museum, Buffalo Bill Center of the West Cody, Wyoming.
Colt Model 1903 Pocket Hammerless
A derringer is a small handgun that is neither a revolver, semi-automatic pistol, nor machine pistol. It is not to be confused with mini-revolvers or pocket pistols, although some later derringers were manufactured with the pepperbox configuration. The modern derringer is often multi barreled, and is generally the smallest usable handgun of any given caliber and barrel length due to the lack of a moving action, which takes up more space behind the barrel. It is frequently used by women because it is easily concealable in a purse or a stocking.
An original Philadelphia Deringer made by Henry Deringer. This was the pocket pistol used by John Wilkes Booth in the assassination of Abraham Lincoln.
A flintlock muff pistol with unscrewable barrel: the 18th century precursor to the caplock deringer
Close-up of Philadelphia Deringer's markings
.41 Rimfire cartridge
