Baking-powder definition

A mixture of baking soda, starch, and at least one slightly acidic compound such as cream of tartar that works as a leavening agent in baking by releasing carbon dioxide when mixed with a liquid, such as milk or water.

A leavening agent that raises dough by the gas (carbon dioxide) produced when baking soda and acid react in the presence of water: it usually contains baking soda mixed with either starch or flour, plus cream of tartar or another acid-forming substance such as anhydrous sodium aluminum sulfate.

A mixture of baking soda, a nonreactive filler (such as starch), and at least one slightly acidic compound (such as cream of tartar). Baking powder works as a leavening agent in baking by releasing carbon dioxide when mixed with a liquid, such as milk or water.