Baker's yeast in a bowl.Licensed from iStockPhoto
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
a yeast (Saccharomyces cerevisiae) used in baking as a leavening, as for certain breads
Used by arrangement with John Wiley & Sons, Inc.
nounThe American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
A commercial preparation consisting of dried cells of one or more strains of the fungus Saccharomyces cerevisiae, used as a leavening in baking.