Mixed martial arts cage
Mixed martial arts cage is the typical combat area of most mixed martial arts (MMA) promotions.
According to the Unified Rules of Mixed Martial Arts, an MMA competition or exhibition may be held in a ring or a fenced area. The fenced area can be round or have at least six sides. Cages vary: some replace the metal fencing with a net, others have a different shape from an octagon, as the term "The Octagon" is trademarked by the UFC (although the 8-sided shape itself is not trademarked). The fenced area is called a cage generically, or a hexagon, an octagon or an octagon cage, depending on the shape.
On the contrary amateur MMA endorsed by United World Wrestling uses open wrestling mat, instead.