Oss (greeting)
Oss also Osu (Japanese: おす or おっす) is a casual greeting in Japanese typically associated with male practitioners of Japanese martial arts such as karate, kendo, and judo. "Oss!" is used outside Japan by some practitioners of Japanese martial arts and derived systems, e.g. Brazilian jiu-jitsu. There are various theories as to its origin, but the term is believed to have originated before WWII in the Imperial Japanese Navy, at the Kyoto Budo Senmon Gakko of the Dai Nippon Butoku Kai, or the sumo club at Takushoku University.