Cereal and Cereal grass

Cereal noun - Grass whose starchy grains are used as food: wheat; rice; rye; oats; maize; buckwheat; millet.

Cereal grass is a synonym for cereal. In some cases you can use "Cereal grass" instead a noun "Cereal".

Cereal grass noun - Grass whose starchy grains are used as food: wheat; rice; rye; oats; maize; buckwheat; millet.

Cereal is a synonym for cereal grass. You can use "Cereal" instead a noun phrase "Cereal grass".