English▸ plural noun [treated as singular] a contagious disease of tropical countries, caused by a bacterium that enters skin abrasions and gives rise to small crusted lesions which may develop into deep ulcers. Also called framboesia
The bacterium is the spirochaeteTreponema pallidum subsp. pertenue.
– ORIGIN late 17th century: probably from Carib yaya, from an indigenous South American language.