cucumber vs Cucumis sativus

cucumber and Cucumis sativus both are nouns.

Word	Noun	Adjective	Verb	Adverb
cucumber	Yes	No	No	No
Cucumis sativus	Yes	No	No	No

As nouns, cucumber and Cucumis sativus are synonyms defined as:

cucumber and Cucumis sativus: a melon vine of the genus Cucumis; cultivated from earliest times for its cylindrical green fruit

Other synonyms of cucumber include cucumber vine.

cucumber (noun)	Cucumis sativus (noun)
cylindrical green fruit with thin green rind and white flesh eaten as a vegetable; related to melons	a melon vine of the genus Cucumis; cultivated from earliest times for its cylindrical green fruit
a melon vine of the genus Cucumis; cultivated from earliest times for its cylindrical green fruit