- yeast
- O.E. gist "yeast," common W.Gmc. source (cf. M.H.G. gest, Ger. Gischt "foam, froth," O.H.G. jesan, Ger. gären "to ferment"), from PIE *jes- "boil, foam, froth" (cf. Skt. yasyati "boils, seethes," Gk. zein "to boil," Welsh ias "seething, foaming").