\ ˈyēst How to pronounce yeast (audio) , especially Southern and Midland US ˈēst \

Definition of yeast

 (Entry 1 of 2)

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 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


yeasted; yeasting; yeasts

Definition of yeast (Entry 2 of 2)

Other Words from yeast


yeast-like or less commonly yeastlike \ ˈyēst-​ˌlīk How to pronounce yeast (audio) , especially Southern and Midland US  ˈēst-​ \ adjective

Examples of yeast in a Sentence

Noun taxation without representation proved to be the yeast of rebellion
Recent Examples on the Web: Noun Sourdoughs were so named because of the fermenting dough many of them carried in place of yeast. John Schandelmeier, Anchorage Daily News, 31 July 2022 To produce each bottle extra-dry blends are fermented using a unique homemade strain of yeast, then ceramic-filtered, fusing new technology with traditional production methods. Lela London, Forbes, 27 June 2022 Then, sample the population, and check the relative levels of normal and mutant yeast. John Timmer, Ars Technica, 11 June 2022 Yeast infections happen when there’s an overgrowth of yeast that disrupts the vagina’s delicate microbiome. Alyssa Jung, Good Housekeeping, 2 May 2022 The researchers’ previous experience proved pivotal in making up for the absence of the yeast. Kristen Rogers, CNN, 23 Mar. 2022 One received two spoons of yeast every day, and the other a vitamin C tablet. Grace Browne, Wired, 14 Mar. 2022 Candida auris is a type of yeast that can cause severe illness, like bloodstream and wound infections, particularly for people with serious medical conditions in hospitals and nursing homes. oregonlive, 29 Dec. 2021 Yeast Sealed packets of yeast will remain active for up to two years stored at room temperature. Paul Stephen, San Antonio Express-News, 13 Dec. 2021 Recent Examples on the Web: Verb With bread and yeast hard to find early in the pandemic, more people began baking sourdough bread at home. Carol Deptolla, Milwaukee Journal Sentinel, 26 Jan. 2022 Directions: In a large bowl, mix together yeast, sugar and 2 ½ cups of warm water (warm bath water temp). Karla Alindahao, Forbes, 16 June 2021 Oddly, cancer cells also metabolize sugars through fermentation, in a manner analogous to yeast cells. Sam Kean, WSJ, 15 June 2021 Another issue is that the drug is not suitable for one group of people particularly prone to yeast infections: pregnant people. Carolyn L. Todd, SELF, 3 June 2021 But the operation still feels kind of smalltown, punctuated by the fact that a Yuengling family member followed the recipes and yeast down to Texas to begin a historic expansion for the company. Sarah Blaskovich, Dallas News, 11 May 2021 Supply shortages have made flour, beans, pasta, and yeast hot commodities. Amanda Mull, The Atlantic, 5 Mar. 2021 Witness the disappearing flour and yeast off grocery store shelves, the uptick in sourdough. Washington Post, 23 Dec. 2020 For recipes with drier doughs and longer mix times like pasta, tortilla or yeasted doughs, add the discard directly to the other ingredients during mixing. Erin Jeanne Mcdowell, New York Times, 28 Apr. 2020 See More

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.

First Known Use of yeast


before the 12th century, in the meaning defined at sense 1a


1819, in the meaning defined above

History and Etymology for yeast


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

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The first known use of yeast was before the 12th century

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yeast cake

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Last Updated

13 Aug 2022

Cite this Entry

“Yeast.” Dictionary, Merriam-Webster, Accessed 19 Aug. 2022.

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More Definitions for yeast


\ ˈyēst How to pronounce yeast (audio) \

Kids Definition of yeast

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)


\ ˈyēst How to pronounce yeast (audio) \

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

Other Words from yeast

yeastlike \ -​ˌlīk How to pronounce yeast (audio) \ adjective

More from Merriam-Webster on yeast

Nglish: Translation of yeast for Spanish Speakers

Britannica English: Translation of yeast for Arabic Speakers Encyclopedia article about yeast


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