leaven

leav·en  (lvn)

n.

1. An agent, such as yeast, that causes batter or dough to rise, especially by fermentation.

2. An element, influence, or agent that works subtly to lighten, enliven, or modify a whole.

tr.v. leav·ened, leav·en·ing, leav·ens

1. To add a rising agent to.

2. To cause to rise, especially by fermentation.

3. To pervade with a lightening, enlivening, or modifying influence.

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[Middle English, from Old French levain, from Vulgar Latin *levmen, from Latin levre, to raise; see leg^wh- in Indo-European roots.]

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leaven [lev-ven]

Noun

also leavening

1. any substance, such as yeast, that produces fermentation in dough and makes it rise

2. an influence that produces a gradual change

Verb

1. to cause fermentation in (dough)

2. to spread through, causing a gradual change [Latin levare to raise]

Thesaurus

Noun	1.	leaven - a substance used to produce fermentation in dough or a liquid leavening substance - a particular kind or species of matter with uniform properties; "shigella is one of the most toxic substances known to man" baking powder - any of various powdered mixtures used in baking as a substitute for yeast sourdough - a leaven of dough in which fermentation is active; used by pioneers for making bread barm, yeast - a commercial leavening agent containing yeast cells; used to raise the dough in making bread and for fermenting beer or whiskey
	2.	leaven - an influence that works subtly to lighten or modify something; "his sermons benefited from a leavening of humor" leavening imponderable - a factor whose effects cannot be accurately assessed; "human behavior depends on many imponderables"
Verb	1.	leaven - cause to puff up with a leaven; "unleavened bread" prove, raise lift, raise, elevate, get up, bring up - raise from a lower to a higher position; "Raise your hands"; "Lift a load"