yeast
noun
1. a commercial leavening agent containing yeast cells; used to raise the dough in making bread and for fermenting beer or whiskey
Similar word(s): barm
Definition categories: substance, leaven, leavening
2. any of various single-celled fungi that reproduce asexually by budding or division
verb
1. To ferment.
2. (of something prepared with a yeasted dough) To rise.