longanberry vs fruit tree

longanberry and fruit tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
longanberry	Yes	No	No	No
fruit tree	Yes	No	No	No

As nouns, fruit tree is a hypernym of longanberry; that is, fruit tree is a word with a broader meaning than longanberry:

longanberry: tree of southeastern Asia to Australia grown primarily for its sweet edible fruit resembling litchi nuts; sometimes placed in genera Euphorbia or Nephelium
fruit tree: tree bearing edible fruit

longanberry (noun)	fruit tree (noun)
Asian fruit similar to litchi	tree bearing edible fruit
tree of southeastern Asia to Australia grown primarily for its sweet edible fruit resembling litchi nuts; sometimes placed in genera Euphorbia or Nephelium