.32 ACP also known as the .32 Automatic is a pistol

Pistol

When distinguished as a subset of handguns, a pistol is a handgun with a chamber that is integral with the barrel, as opposed to a revolver, wherein the chamber is separate from the barrel as a revolving cylinder. Typically, pistols have an effective range of about 100 feet.-History:The pistol...

 cartridge. It is a semi-rimmed

Rim (firearms)

A rim is an external flange that is machined, cast, molded, stamped or pressed around the bottom of a firearms cartridge. The rim may serve a number of purposes, the most common being as the place for the extractor to engage...

, straight-walled cartridge developed by firearms designer John Browning

John Browning

John Moses Browning , born in Ogden, Utah, was an American firearms designer who developed many varieties of military and civilian firearms, cartridges, and gun mechanisms, many of which are still in use around the world...

, initially for use in the FN M1900

FN M1900

The FN Browning M1900 is a single action, semi-automatic pistol designed ca. 1896 by John Browning for Fabrique Nationale de Herstal and produced in Belgium at the turn of the century...

 semi-automatic pistol. It was introduced in 1899 by Fabrique Nationale, and is also known as the 7.65x17mm Browning SR or 7.65 mm Browning.
John Browning engineered a number of modern semi-automatic pistol mechanisms and cartridges.