Dictionary-Definition.com :: Leaven definition

Definition of 'leaven'

noun

A substance used to produce fermentation in dough or a liquid [syn: leaven, leavening]

noun

An influence that works subtly to lighten or modify something; "his sermons benefited from a leavening of humor" [syn: leaven, leavening]

verb

Cause to puff up with a leaven; "unleavened bread" [syn: raise, leaven, prove]

From: GCIDE

Leaven \Leav"en\, n. [OE. levain, levein, F. levain, L. levamen alleviation, mitigation; but taken in the sense of, a raising, that which raises, fr. levare to raise. See Lever, n.]
1. Any substance that produces, or is designed to produce, fermentation, as in dough or liquids; esp., a portion of fermenting dough, which, mixed with a larger quantity of dough, produces a general change in the mass, and renders it light; yeast; barm. [1913 Webster]
2. Anything which makes a general assimilating (especially a corrupting) change in the mass. [1913 Webster]
Beware of the leaven of the Pharisees, which is hypocrisy. --Luke xii. 1. [1913 Webster]

From: GCIDE

Leaven \Leav"en\, v. t. [imp. & p. p. Leavened; p. pr. & vb. n. Leavening.]
1. To make light by the action of leaven; to cause to ferment. [1913 Webster]
A little leaven leaveneth the whole lump. --1 Cor. v. 6. [1913 Webster]
2. To imbue; to infect; to vitiate. [1913 Webster]
With these and the like deceivable doctrines, he leavens also his prayer. --Milton. [1913 Webster]

Leaven
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.
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).