Barm n. : Foam rising upon beer, or other malt liquors, when fermenting, and used as leaven in making bread and in brewing; yeast.

Barm n. : The lap or bosom.

Example:
Does anyone else traditionally eat Barm Loaf for breakfast on Christmas Day?

Taxonomy
barm cake, free encyclopedia, leaven, bread, Reinhart, wine, search, foam, scum, alcoholic beverages, feedstock, industrial ethanol, fermentation, batch, ground, tubs, synonym, cultures.

Defination from the web:
Barm is the foam, or scum, formed on the top of liquor (i.e. fermented alcoholic beverages such as beer or wine, or feedstock for hard liquor or ... It is applied equally to yeast-leavened bread, without implying the use of sourdough or barm leavens. ...