English▸ noun [mass noun] a microscopic fungus consisting of single oval cells that reproduce by budding, and capable of converting sugar into alcohol and carbon dioxide.
Genus Saccharomyces, subdivision Ascomycotina.
▪ a greyish-yellow preparation of the yeast fungus obtained chiefly from fermented beer, used as a fermenting agent, to raise bread dough, and as a food supplement.
▪ [count noun] Biology any unicellular fungus that reproduces vegetatively by budding or fission, including forms such as candida that can cause disease.
– ORIGIN Old English gist, gyst, of Germanic origin; related to Dutch gist and German Gischt ‘froth, yeast’, from an Indo-European root shared by Greek zein ‘to boil’.