'Leavening' definitions:

Definition of 'leavening'

noun

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

noun

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

From: GCIDE

Leavening \Leav"en*ing\, n.
1. The act of making light, or causing to ferment, by means of leaven. [1913 Webster]
2. That which leavens or makes light. --Bacon. [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]