sweet lime vs Citrus limon

sweet lime and Citrus limon both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweet lime	Yes	No	No	No
Citrus limon	Yes	No	No	No

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

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

Other hypernyms of sweet lime include lemon, lemon tree.

sweet lime (noun)	Citrus limon (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