■ noun
1》 a microscopic single-celled fungus capable of converting sugar into alcohol and carbon dioxide. [ Saccharomyces cerevisiae ( brewer's ~ ) and related species.]
↘a greyish-yellow preparation of this obtained chiefly from fermented beer, used as a fermenting agent, to raise bread dough, and as a food supplement.
2》 Biology any unicellular fungus that reproduces vegetatively by budding or fission, e.g. candida.
Origin
OE, of Gmc origin.