what's the difference between cereals and porridge

[KLPNO]

Hello, everybody.
I wonder what's the difference between cereals and porridge. For example, I met sentence like this one:

A dry breakfast cereal for infants, other than porridge, that requires the user to add milk or water before it is ready for consumption. Examples include Heinz 4 month Raspberry & Strawberry Cereal, Gerber Mixed Grain Cereal for Baby and Gerber Rice Ber.

I have to admit that the difference is somewhat unclear to me.

[diverhank]

Porridge refers to something whose ingredients are cooked together. Cereal and milk are not cooked, just blended.

[KLPNO]

Thank you very much, diverbank.