wild plum vs goose plum

wild plum and goose plum both are nouns.

Word	Noun	Adjective	Verb	Adverb
wild plum	Yes	No	No	No
goose plum	Yes	No	No	No

As nouns, goose plum is a hyponym of wild plum; that is, goose plum is a word with a more specific, narrower meaning than wild plum:

wild plum: an uncultivated plum tree or shrub
goose plum: wild plum trees of eastern and central North America having red-orange fruit with yellow flesh

wild plum (noun)	goose plum (noun)
fruit of the wild plum of southern United States	wild plum trees of eastern and central North America having red-orange fruit with yellow flesh
an uncultivated plum tree or shrub