Brazilian Jiu-Jitsu (BJJ; /dʒuːˈdʒɪtsuː/; Portuguese: [ˈʒiw ˈʒitsu], [ˈʒu ˈʒitsu], jiu-jitsu brasileiro) is a martial art and combat sport based on ground fighting (ne-waza) and submission holds. It focuses on the skill of taking an opponent to the ground, controlling one's opponent, gaining a dominant position, and using a number of techniques to force them into submission via joint locks or chokeholds.

Brazilian Jiu-Jitsu was first developed around 1920 by Brazilian brothers Carlos, Oswaldo, Gastão Jr., George, and Hélio Gracie, after Carlos was taught traditional Kodokan judo by a travelling Japanese judoka, Mitsuyo Maeda, in 1917. Later they developed their own self-defense system named Gracie Jiu-Jitsu. BJJ eventually came to be its own defined combat sport through the innovations, practices, and adaptation of Gracie Jiu-Jitsu and Judo, and became an essential martial art for modern MMA.

Source: Wikipedia