grouseberry vs blueberry

grouseberry and blueberry both are nouns.

Word	Noun	Adjective	Verb	Adverb
grouseberry	Yes	No	No	No
blueberry	Yes	No	No	No

As nouns, blueberry is a hypernym of grouseberry; that is, blueberry is a word with a broader meaning than grouseberry:

grouseberry: shrub of northwestern North America bearing red berries
blueberry: any of numerous shrubs of the genus Vaccinium bearing blueberries

Other hypernyms of grouseberry include blueberry bush.

grouseberry (noun)	blueberry (noun)
shrub of northwestern North America bearing red berries	sweet edible dark-blue berries of either low-growing or high-growing blueberry plants
	any of numerous shrubs of the genus Vaccinium bearing blueberries