Barm

n.	1.	Foam rising upon beer, or other malt liquors, when fermenting, and used as leaven in making bread and in brewing; yeast.
	1.	The lap or bosom.

Noun

1.

barm - a commercial leavening agent containing yeast cells; used to raise the dough in making bread and for fermenting beer or whiskey Synonyms: yeast

brewer's yeast, leaven, leavening, mother, yeast, yeast cake