cold cereal vs cereal

cold cereal and cereal both are nouns.

Word	Noun	Adjective	Verb	Adverb
cold cereal	Yes	No	No	No
cereal	Yes	Yes	No	No

As nouns, cereal is a hypernym of cold cereal; that is, cereal is a word with a broader meaning than cold cereal:

cold cereal (noun)	cereal (noun)
a cereal that is not heated before serving	a breakfast food prepared from grain
	foodstuff prepared from the starchy grains of cereal grasses
	grass whose starchy grains are used as food: wheat, rice, rye, oats, maize, buckwheat, millet

cold cereal (adjective)	cereal (adjective)
	made of grain or relating to grain or the plants that produce it