barm Meaning, Definition & Usage

  1. noun a commercial leavening agent containing yeast cells; used to raise the dough in making bread and for fermenting beer or whiskey
    yeast.

WordNet

Barm noun
Etymology
OE. berme, AS. beorma; akin to Sw. bärma, G. bärme, and prob. L. fermenium. *93.
Definitions
  1. Foam rising upon beer, or other malt liquors, when fermenting, and used as leaven in making bread and in brewing; yeast. Shak.
Barm noun
Etymology
OE. bearm, berm, barm, AS. beorma; akin to E. bear to support.
Definitions
  1. The lap or bosom. Obs. Chaucer.

Webster 1913