The phrase "dry cereal" refers to a breakfast food that does not need to be cooked or mixed with milk or other liquids. It can be eaten as it is straight from the box. Full definition
He won't be eating much in the way of solids at this point, so a box of dry cereal plus a few jars of puree should be enough to hold him over. (havebabywilltravel.com)
Choose items that won't be easily broken and that can be eaten while you hold him in line like dry cereal or yogurt melts. (disneybaby.com)
Another quick breakfast is yogurt mixed with dry cereal and a sprinkling of nuts. (laurafuentes.com)