Definition of "magnum" in English

noun

1. A bottle containing 1.5 liters of fluid, double the volume of a standard wine bottle.

2. (firearms) A powerful firearm cartridge, often derived from a shorter, less powerful cartridge calibre that uses the same bullet.

3. (by extension) A handgun that fires a cartridge of this calibre; chiefly a revolver, but rarely an autoloader firing an unusually powerful calibre.