from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Any of various unicellular fungi of the genus Saccharomyces, especially S. cerevisiae, reproducing by budding and from ascospores and capable of fermenting carbohydrates.
- n. Any of various similar fungi.
- n. Froth consisting of yeast cells together with the carbon dioxide they produce in the process of fermentation, present in or added to fruit juices and other substances in the production of alcoholic beverages.
- n. A powdered or compressed commercial preparation, having yeast cells and inert material such as meal and used chiefly as a leavening agent or as a dietary supplement.
- n. Foam; froth.
- n. An agent of ferment or activity: political agitators who are the yeast of revolution.
- intransitive v. To ferment.
- intransitive v. To froth or foam.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An often humid, yellowish froth produced by fermenting malt worts, and used to brew beer, leaven bread, and also used in certain medicines.
- n. A type of single-celled fungus.
- n. A compressed cake or dried granules of this substance used for mixing with flour to make bread dough rise.
- n. A frothy foam.
- v. To ferment.
- v. To rise.
from the GNU version of the Collaborative International Dictionary of English
- n. The foam, or troth (top yeast), or the sediment (bottom yeast), of beer or other in fermentation, which contains the yeast plant or its spores, and under certain conditions produces fermentation in saccharine or farinaceous substances; a preparation used for raising dough for bread or cakes, and making it light and puffy; barm; ferment.
- n. Spume, or foam, of water.
from The Century Dictionary and Cyclopedia
- n. A yellowish substance, having an acid reaction, produced during the alcoholic fermentation of saccharine fluids, rising partly to the surface in the form of a frothy, flocculent, viscid matter (top or surface yeast), and partly falling to the bottom (bottom or sediment yeast).
- n. Spumc or foam of water; froth.
- To ferment.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. any of various single-celled fungi that reproduce asexually by budding or division
- n. a commercial leavening agent containing yeast cells; used to raise the dough in making bread and for fermenting beer or whiskey
Middle English yeest, from Old English gist.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Old English ġiest, from Proto-Germanic *jestuz. (Wiktionary)