sweet lime vs lemon tree

sweet lime and lemon tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweet lime	Yes	No	No	No
lemon tree	Yes	No	No	No

As nouns, lemon tree is a hypernym of sweet lime; that is, lemon tree is a word with a broader meaning than sweet lime:

sweet lime: lemon tree having fruit with a somewhat insipid sweetish pulp
lemon tree: a small evergreen tree that originated in Asia but is widely cultivated for its fruit

Other hypernyms of sweet lime include Citrus limon, lemon.

sweet lime (noun)	lemon tree (noun)
lemon tree having fruit with a somewhat insipid sweetish pulp	a small evergreen tree that originated in Asia but is widely cultivated for its fruit