leaven

[lev-uh n] /ˈlɛv ən/

noun

a substance, as yeast or baking powder, that causes fermentation and expansion of dough or batter.

fermented dough reserved for producing fermentation in a new batch of dough.

an element that produces an altering or transforming influence.

verb (used with object)

to add leaven to (dough or batter) and cause to rise.

to permeate with an altering or transforming element.

Origin

1300-50; Middle English levain < Anglo-French, Old French levain < Vulgar Latin *levāmen, equivalent to Latin levā(re) to raise + -men deverbal noun suffix (probably not continuous with Latin levāmen means of alleviating, solace)

Examples from the web for leaven

The ancient leaven bread was made by the dough being left in a warm place till it began to ferment.
Our ancestors also quickly figured out how to harness yeast to ferment alcohol and leaven bread.
Biotechnology began centuries ago when people began using yeasts and bacteria to leaven bread and ferment cheeses.
It can leaven the purposefully self-aggrandizing nature of a job interview.
The departure of such strivers has removed the leaven from the housing estates that they quit.
But in her last three films, she has learned to smartly dramatize her rage or leaven it with beguiling wit.
Which the writers are always sure to leaven with some cool ninja action.
The aristocratic leaven in the loaf disappeared completely.
There were no cries of censorship from the cable news stations, which had been hungering for pictures to leaven the hours of talk.
Such an individual is yeast that can leaven an entire loaf.

British Dictionary definitions for leaven

leaven

/ˈlɛvən/

noun

any substance that produces fermentation in dough or batter, such as yeast, and causes it to rise

a piece of such a substance kept to ferment a new batch of dough

an agency or influence that produces a gradual change

verb (transitive)

to cause fermentation in (dough or batter)

to pervade, causing a gradual change, esp with some moderating or enlivening influence

Word Origin

C14: via Old French ultimately from Latin levāmen relief, (hence, raising agent, leaven), from levāre to raise

Word Origin and History for leaven

mid-14c., from Old French levain "leaven, sourdough" (12c.), from Latin levamen "alleviation, mitigation," but used in Vulgar Latin in its literal sense of "a means of lifting, something that raises," from levare "to raise" (see lever). Figurative use from late 14c.

c.1400, from leaven (n.). Related: Leavened; leavening.

leaven in the Bible

(1.) Heb. seor (Ex. 12:15, 19; 13:7; Lev. 2:11), the remnant of dough from the preceding baking which had fermented and become acid. (2.) Heb. hamets, properly "ferment." In Num. 6:3, "vinegar of wine" is more correctly "fermented wine." In Ex. 13:7, the proper rendering would be, "Unfermented things [Heb. matstsoth] shall be consumed during the seven days; and there shall not be seen with thee fermented things [hamets], and there shall not be seen with thee leavened mass [seor] in all thy borders." The chemical definition of ferment or yeast is "a substance in a state of putrefaction, the atoms of which are in a continual motion." The use of leaven was strictly forbidden in all offerings made to the Lord by fire (Lev. 2:11; 7:12; 8:2; Num. 6:15). Its secretly penetrating and diffusive power is referred to in 1 Cor. 5:6. In this respect it is used to illustrate the growth of the kingdom of heaven both in the individual heart and in the world (Matt. 13:33). It is a figure also of corruptness and of perverseness of heart and life (Matt. 16:6, 11; Mark 8:15; 1 Cor. 5:7, 8).