Definitions for "Fold in"
Keywords:  beaten, gently, heavier, mixture, flour
Combining ingredients by lifting and dropping a spoon, in order to incorporate air into the mixture. Eg, while making a sponge cake, you normally fold in the flour into the egg mixture.
Using a spatula, to combine fragile substances, such as whipped cream, into a heavier mixture with light, circular motions.
To gently combine a heavier mixture with a more delicate substance such as beaten egg whites or whipped cream without causing a loss of air.