mountain cranberry vs cranberry

mountain cranberry and cranberry both are nouns.

Word	Noun	Adjective	Verb	Adverb
mountain cranberry	Yes	No	No	No
cranberry	Yes	No	No	No

As nouns, cranberry is a hypernym of mountain cranberry; that is, cranberry is a word with a broader meaning than mountain cranberry:

mountain cranberry: low evergreen shrub of high north temperate regions of Europe and Asia and America bearing red edible berries
cranberry: any of numerous shrubs of genus Vaccinium bearing cranberries

mountain cranberry (noun)	cranberry (noun)
tart red berries similar to American cranberries but smaller	very tart red berry used for sauce or juice
low evergreen shrub of high north temperate regions of Europe and Asia and America bearing red edible berries	any of numerous shrubs of genus Vaccinium bearing cranberries