[barm] n [ME berme, fr. OE beorma; akin to L fermentum yeast, fervere to boil, OIr berbaid he boils] (bef. 12c): yeast formed on fermenting malt liquors
BARM
Meaning of BARM in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012