Oss (also written osu) is the all-purpose word of the BJJ mat: a greeting, a yes, a thank-you and a sign that you have understood and are ready to work. You will hear it dozens of times in a single class.
- Also spelled: osu, ossu.
- In BJJ: said when you bow onto the mat, when the coach finishes showing a technique, and when you accept a roll.
- In judo: much less common. Judo players bow and use hai (yes) or stay quiet.
What it means
Oss carries no single dictionary meaning on the mat. Depending on the moment it means yes, I understand, thank you, let's go, or simply hello. The tone does the work: a short, firm oss after the coach demonstrates says you got it; a louder group oss at the start of class is the room agreeing to train hard.
People will give you several origin stories for the word. None of them is settled, so this page stays with how the word is used today.
Where you hear it
- Bowing onto the mat at the start of class and off it at the end.
- After the instructor finishes explaining a move and asks if everyone is clear.
- When a training partner asks if you want to roll and you accept.
- After a round, with the handshake or fist bump, as a thank-you for the roll.
- In messages and comments between grapplers, where it works as a sign-off.
How to use it
Match the room. Some academies say oss constantly, others barely at all, and a visitor who shouts it every thirty seconds stands out for the wrong reasons. Watch what the higher belts do in the first ten minutes and copy that.
Say it once and mean it. One clear oss is an acknowledgement; a stream of them is noise. Use it to answer the coach, to accept a roll and to thank a partner, and let your training do the rest of the talking.
It is also one of the most printed words in the sport. Our BJJ t-shirts carry the lines you hear on the mat.
Related terms
Bow, Sensei, Professor (BJJ), Tap / tapping out, Academy (BJJ).