1911 Encyclopædia Britannica/Yeast

YEAST (O.E. giest or gyst; the root yes-, to boil, ferment, is seen in Sansk. nir-yāsa, exudations from trees, and Gr. ζεέιν, to boil), a cellular organism produced in the alcoholic fermentation of saccharine liquids (see Fungi, Fermentation, Brewing).