The word Parabellum is derived from the Latin saying Si vis Pacem, para bellum, meaning 'If you seek peace, prepare for war'. So it means 'prepare for war' or 'to war'. Its weight is around 12.5 grams and around 4.5 grams empty. The 9x19mm has a muzzle velocity of 350 m/s and muzzle energy equal to 490 J. No variations to the original cartridge where made during the war but later on, modifications were eventually made such as creating hollowpoint rounds.
It was designed in 1902 by Georg Luger, by whom the Luger pistol was famously named. The German weapons manufacturer Deutsche Waffen und Munitionsfabriken (DWM) created it and it is now the most popular pistol cartridge.
Many pistol and machine pistols, mostly German, have and currently still use the 9mm cartridge, including the Walther, Luger and MP40; eventually, the 9 mm Para has became the world's service pistol's round of choice, form the US Army's M9 to the Russian Yarigyn and GSh-18, which are chambered for the overpressurised armour-piercing version.