Citrus limetta vs lemon tree

Citrus limetta and lemon tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
Citrus limetta	Yes	No	No	No
lemon tree	Yes	No	No	No

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

Citrus limetta: 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 Citrus limetta include Citrus limon, lemon.

Citrus limetta (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