What does the word yeast mean?

Usage examples for yeast

  1. Bread mixed with two yeast cakes may be made and baked in about three hours. – Better Meals for Less Money by Mary Green
  2. Keep things stirred up- human yeast cakes, only they get to thinking they're the dough, too. – The Wrong Twin by Harry Leon Wilson
  3. You didn't put yeast in those biscuits! – The Wishing-Ring Man by Margaret Widdemer