yeast

noun \ ˈyēst , especially Southern and Midland US ˈēst \

|Updated on: 14 Jun 2018

Definition of yeast

1 a : 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 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

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

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yeast-like

or less commonly yeastlike play \ˈyēst-ˌlīk, especially Southern and Midland US ˈēst-\ adjective

See yeast defined for English-language learners

See yeast defined for kids

Examples of yeast in a Sentence

taxation without representation proved to be the yeast of rebellion

Recent Examples of yeast from the Web

Plus, some supplement ingredients, including caffeine powder and red yeast rice, have been shown to be potentially dangerous even in low doses.

— amanda macmillan, Health.com, "Is It Possible to Take Too Many Vitamins?," 6 June 2018
Three types of beer are highlighted at the event: real, which stands for real ale;, wild beers that contain wild yeast; and woody, or beer aged in wooden barrels.

— kellie hwang, azcentral, "Best food and drink events in Phoenix this summer," 4 June 2018
The yeast the scientists found was a rare hybrid strain different from strains used to brew ale today.

— marissa fessenden, Smithsonian, "Australian Brewers Are Making Beer From Yeast Found on a Shipwreck," 7 May 2018
Bentley still takes five supplements a day: a multivitamin to prevent dry eyes, magnesium to prevent cramps while exercising, red yeast rice to prevent diabetes, coenzyme Q10 for overall health and vitamin D based on her doctor's recommendation.

— liz szabo, CNN, "Enthusiasm over vitamins often outpaces evidence, experts say," 13 Apr. 2018
DeBenedetti’s creations take advantage of the surrounding agricultural bounty, incorporating hazelnuts and wild yeast from his family’s farm in addition to locally grown white truffles and golden raspberries.

— tim neville, Outside Online, "The Definitive Guide to Visiting the Pacific Northwest," 24 May 2018
So do plants, and yeast — and anything with a cell with a nucleus.

— joanna klein, New York Times, "The Thing Inside Your Cells That Might Determine How Long You Live," 20 May 2018
Brewed with a Belgian yeast, the beer smells of melon and white grapes and tastes a bit grassy.

— gary dzen, BostonGlobe.com, "Four wine beers you should try immediately," 15 May 2018
The first step, often recognized only in retrospect, likely will be an insight in yeast or fish or mice without any obvious relevance to a new medical breakthrough.

— mark c. fishman, STAT, "The miracle of medicines," 7 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'yeast.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of yeast

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

NEW! Time Traveler

First Known Use: before 12th century

in the meaning defined at sense 1a

See Words from the same year

yeast Synonyms

Phrases

shot in the arm;

Other Food Terms

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

yeast

verb

Definition of yeast

yeasted; yeasting; yeasts

intransitive verb

: ferment, froth

Recent Examples of yeast from the Web

Same for dozens of styles of fish stew, yeasted rolls, cakes, and pies found around the world.

— National Geographic, "The Secret History of the World's Priciest Spice," 3 May 2017

First Known Use of yeast

1819

in the meaning defined above

See Words from the same year

NEW! Time Traveler

Other Biochemistry Terms

bile, biodegradable, capsaicin, keratin, metabolism

YEAST Defined for English Language Learners

yeast

noun

Definition of yeast for English Language Learners

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

YEAST Defined for Kids

yeast

noun \ ˈyēst \

Definition of yeast for Students

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)

Medical Dictionary

yeast

noun \ ˈyēst \

medical Definition of yeast

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

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