Are we talking breakfast foods? 

Not the processed ones, not the cornflakes and the sugar puffs of the world. We are talking about pure cereal crops. 

To be fair, the heavily marketed cereal boxes that you’ll find in the breakfast aisle do contain some amount of cereal. Hence the name.

What are cereal crops? 

Grass-related plants that grow seed/grain for human/animal consumption. Like wheat, rye, millet and oat

So basically grains?

Yupp, they are pretty much the same thing – in our eyes. We prefer writing grains, because the term seems more specific to the edible part of the plant.