baking soda noun
Learner's definition of BAKING SODA
[noncount]
: a kind of salt that is used to make baked foods (such as cookies and breads) light and fluffy小苏打（发酵粉的成分之一） ◊ Baking soda is one of the ingredients in baking powder.小苏打（发酵粉的成分之一）
— called also bicarb, bicarbonate of soda, sodium bicarbonate