¹yeast

noun \ˈyēst, especially Southern & Midland ˈēst\

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

Full Definition of YEAST

a : a yellowish surface froth or sediment that occurs especially in saccharine liquids (as fruit juices) in which it promotes alcoholic fermentation, consists largely of cells of a fungus (as the saccharomyces, Saccharomyces cerevisiae), and is used especially in the making of alcoholic liquors and as a leaven in baking

b : a commercial product containing yeast fungi in a moist or dry medium

c (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

archaic : the foam or spume of waves

: something that causes ferment or activity <were all seething with the yeast of revolt — J. F. Dobie>

See yeast defined for English-language learners

See yeast defined for kids

Origin of YEAST

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

Related to YEAST

Synonyms: boost, encouragement, goad, impetus, incentive, incitation, incitement, instigation, momentum, motivation, provocation, spur, stimulant, stimulus, impulse

Antonyms: counterincentive, disincentive

Other Food Terms

Reuben, calamari, chuck, curry, edamame, foie gras, hummus, leaven, nonpareil, peel

Rhymes with YEAST

beast, east, feast, fleeced, least, piste, priest, reest, triste

²yeast

verb

Definition of YEAST

intransitive verb

: ferment, froth

First Known Use of YEAST

1819

Other Biochemistry Terms

bile, biodegradable, capsaicin, keratin, metabolism

YEAST Defined for Kids

yeast

noun \ˈyēst\

Definition of YEAST for Kids

: a single-celled fungus that ferments sugar to produce alcohol and carbon dioxide

: 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)

Medical Dictionary

yeast

noun \ˈyēst\

Medical Definition of YEAST

: 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

: 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

: a commercial product containing yeast cells in a moist or dry medium

—yeast·like \-ˌlīk\ adjective