I. ˈyēst, chiefly dial ˈēst noun
( -s )
Etymology: Middle English yest, from Old English gist, giest; akin to Old Norse jastr yeast, Middle High German jest foam, Old High German jesan to ferment, Greek zestos boiled, zein to boil, seethe, Sanskrit yasyati it seethes
1.
a. : a usually creamy or yellowish surface froth or sediment that occurs especially in saccharine liquids (as fruit juices or malt worts) in which it promotes alcoholic fermentation, that consists of a suspension of cells of a fungus of the family Saccharomycetaceae, and that is used especially in the making of alcoholic liquors and as a leaven in baking — see bottom yeast , top yeast , zymase
b. : a commercial product containing yeast plants packaged either as moist cakes or dry cakes or granules and used especially as a leaven in baking
c.
(1) : a minute fungus (especially Saccharomyces cerevisiae ) that is present and functionally active in yeast and usually has little or no mycelium but reproduces by budding
(2) : any of various similar fungi especially of the orders Endomycetales and Moniliales
2. : something resembling the froth of yeast fermentation (as the foam or spume of waves)
they melt into thy yeast of waves — Lord Byron
3. : something that causes ferment or activity, creates a lift or drive, or adds vitality
education is … the great expression of democratic yeast at work — B.G.Gallagher
were all seething with the yeast of revolt — J.F.Dobie
the living yeast of conscience — H.M.Robinson
had taken the yeast out of me — Hugo Johanson
II. verb
( -ed/-ing/-s )
intransitive verb
: ferment , froth
transitive verb
: to impregnate with yeast