yeast
yeast · noun
Definitions
noun
- 1.
A microscopic fungus used in baking and brewing due to its ability to ferment.
- 2.
A preparation of this fungus used in baking or brewing.
- 3.
[figurative]Something that causes activity or ferment.
Forms
plural: yeasts
Related words
Etymology
From Old English gist ("yeast, froth"), from Proto-Germanic jestuz.