Cucumis sativus vs cucumber

Cucumis sativus and cucumber both are nouns.

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

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

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

Other synonyms of Cucumis sativus include cucumber vine.

Cucumis sativus (noun)	cucumber (noun)
a melon vine of the genus Cucumis; cultivated from earliest times for its cylindrical green fruit	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