leavening vs leaven

leavening and leaven both are nouns.

Word	Noun	Adjective	Verb	Adverb
leavening	Yes	No	No	No
leaven	Yes	No	Yes	No

As nouns, leavening and leaven are synonyms defined as:

leavening and leaven: an influence that works subtly to lighten or modify something

As nouns, leavening and leaven are synonyms defined as:

leavening and leaven: a substance used to produce fermentation in dough or a liquid

leavening (noun)	leaven (noun)
an influence that works subtly to lighten or modify something	an influence that works subtly to lighten or modify something
a substance used to produce fermentation in dough or a liquid	a substance used to produce fermentation in dough or a liquid

leavening (verb)	leaven (verb)
	cause to puff up with a leaven