dohyo
The ring, made of compacted clay, in which a sumo wrestling match is held.
Sumo ’bots also tend to have very low ground clearance since they operate on dohyos, which have a very smooth rubberized running surface; […]
Where it comes from
Borrowed from Japanese 土(ど)俵(ひょう) (dohyō).
Adapted from the Wiktionary entry dohyo (CC BY-SA 4.0).