quince vs fruit tree

quince and fruit tree both are nouns.

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

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

quince: small Asian tree with pinkish flowers and pear-shaped fruit; widely cultivated
fruit tree: tree bearing edible fruit

quince (noun)	fruit tree (noun)
aromatic acid-tasting pear-shaped fruit used in preserves	tree bearing edible fruit
small Asian tree with pinkish flowers and pear-shaped fruit; widely cultivated