avocado vs fruit tree

avocado and fruit tree both are nouns.

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

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

avocado (noun)	fruit tree (noun)
a pear-shaped tropical fruit with green or blackish skin and rich yellowish pulp enclosing a single large seed	tree bearing edible fruit
tropical American tree bearing large pulpy green fruits

avocado (adjective)	fruit tree (adjective)
of the dull yellowish green of the meat of an avocado