Citrus limon vs lemon tree

Citrus limon and lemon tree both are nouns.

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

As nouns, Citrus limon and lemon tree are synonyms defined as:

Citrus limon and lemon tree: a small evergreen tree that originated in Asia but is widely cultivated for its fruit

Other synonyms of Citrus limon include lemon.

Citrus limon (noun)	lemon tree (noun)
a small evergreen tree that originated in Asia but is widely cultivated for its fruit	a small evergreen tree that originated in Asia but is widely cultivated for its fruit