i Register
In some senses, barm is marked as obsolete. Watch for register when choosing this word.
noun
bosom
lap
noun
Foam rising upon beer or other malt liquors when fermenting, used as leaven in brewing and making bread; yeast.
[A]nd sometimes make the drink to bear no barm.
In 1577 yeast, called barm, is bought at 9d. the pail.
A small, round, flat individual loaf or roll of bread.
verb
To spurge; foam