Mawashi

Mawashi \muh-WAH-shee\ , noun;
1. A type of loincloth worn by sumo wrestlers

You're welcome... (source)

This word is first attested in English in 1940 from Japanese mawashi (廻し), which is the nominalized stem of mawasu ("to put round"), the transitive form of mawaru ("to go round"). It's related to maru ("circle").

Not that I really need TWO sumo pictures, but this is pretty cool... (source)