BJJ glossary
Quick, plain-language definitions for the terms behind the calculators — scoring positions, sizing, divisions and the health terms that matter on the mat.
A-size (A0–A5)
The standard sizing scale for BJJ gis, keyed roughly to height and weight. There is no universal standard — each brand publishes its own measurements — so an A2 from one maker may fit differently from another's.
ADCC
Abu Dhabi Combat Club: a major submission-grappling (no-gi) organization with its own ruleset, distinct from the IBJJF. Where rules differ, BJJMath's IBJJF tools do not mix the two.
Advantage
A partial point in IBJJF scoring, awarded for nearly completing a scoring action (a swept-but-not-held position, a deep submission attempt). Advantages don't count toward the score itself; they break ties after points and before penalties.
Back control
Controlling an opponent from behind with both hooks (or a body triangle) in. Worth 4 points in IBJJF scoring when stabilized.
Gi (kimono)
The traditional jacket-and-trousers uniform worn in gi BJJ. IBJJF weigh-ins are done in the full gi, which is why competition weight caps are gi-on weights.
Guard pass
Moving from inside an opponent's guard to a dominant position past their legs, establishing control. Worth 3 points in IBJJF scoring.
Herpes gladiatorum
A skin infection (HSV-1) spread by mat contact. Like ringworm and staph, it requires staying off the mat until cleared by a clinician — a hard stop in our return-to-roll tool.
Knee on belly
A control position with the top athlete's knee across the opponent's torso. Worth 2 points in IBJJF scoring.
Master divisions
IBJJF age brackets for competitors 30 and older, in five-year bands (Master 1 = 30–35, up to Master 7 = 61+). Age is figured by competition year minus birth year.
Mount
Sitting on top of a supine opponent's torso with control. Worth 4 points in IBJJF scoring.
No-gi
Grappling without the kimono, typically in rashguard and shorts. Uses different weight caps than gi (nothing added on the scale) and, in many organizations, a different ruleset.
Pearl weave
A common, relatively light gi-jacket weave. Fabric weave and whether it is pre-shrunk strongly affect how much a gi shrinks in the wash.
Ringworm
A fungal skin infection (not a worm) common in grappling. Contagious by contact; mandates time off the mat until treated and cleared.
Submission
A choke or joint-lock that forces an opponent to tap. Ends the match immediately in IBJJF rules, regardless of the score.
Sweep
Reversing position from bottom to top from guard. Worth 2 points in IBJJF scoring when the position is established and held.
Takedown
Bringing a standing opponent to the ground and establishing top position. Worth 2 points in IBJJF scoring.
Time in grade
The minimum time the IBJJF requires an adult to hold a belt before being eligible for the next (e.g. ~2 years at blue). A floor for eligibility, not an expected promotion timeline.