yeast

play

noun \ˈyēst, especially Southern and Midland US ˈēst\

Definition of yeast

1a : a yellowish surface froth or sediment that occurs especially in saccharine liquids (such as fruit juices) in which it promotes alcoholic fermentation, consists largely of cells of a fungus (such as the saccharomyces, Saccharomyces cerevisiae), and is used especially in the making of alcoholic liquors and as a leaven in bakingb : a commercial product containing yeast fungi in a moist or dry mediumc (1) : a unicellular fungus that is present and functionally active in yeast, usually has little or no mycelium, and reproduces by budding (2) : any of various similar fungi
2 archaic : the foam or spume of waves
3 : something that causes ferment or activity were all seething with the yeast of revolt — J. F. Dobie

or less commonly

play \ˈyēst-ˌlīk, especially Southern and Midland US ˈēst-\ adjective

Middle English yest, from Old English gist; akin to Old High German jesen, gesen to ferment, Greek zein to boil

First Known Use: before 12th century

verb

1819

1819

play

noun

: a type of fungus that is used in making alcoholic drinks (such as beer and wine) and in baking to help make dough rise

play

noun \ˈyēst\

1 : a single-celled fungus that ferments sugar to produce alcohol and carbon dioxide
2 : a commercial product containing living yeast cells that is used in baking to make dough rise and in the making of alcoholic beverages (as wine)

play

noun \ˈyēst\

1: a unicellular chiefly ascomycetous fungus (as of the family Saccharomycetaceae) that has usually little or no mycelium, that typically reproduces asexually by budding, and that includes forms (as Saccharomyces cerevisiae) which cause alcoholic fermentation and are used especially in the making of alcoholic beverages and leavened bread
2: a yellowish surface froth or sediment that occurs especially in sugary fermenting liquids (as fruit juices) and consists chiefly of yeast cells and carbon dioxide
3: a commercial product containing yeast cells in a moist or dry medium