cereal

(noun) grass whose starchy grains are used as food: wheat; rice; rye; oats; maize; buckwheat; millet. Synonyms: cereal grass.

(noun) foodstuff prepared from the starchy grains of cereal grasses. Synonyms: grain, food grain.

(noun) a breakfast food prepared from grain.

(adj) made of grain or relating to grain or the plants that produce it. Examples: "A cereal beverage." "Cereal grasses."