Medicago sativa vs alfalfa

Medicago sativa and alfalfa both are nouns.

Word	Noun	Adjective	Verb	Adverb
Medicago sativa	Yes	No	No	No
alfalfa	Yes	No	No	No

As nouns, Medicago sativa and alfalfa are synonyms defined as:

Medicago sativa and alfalfa: important European leguminous forage plant with trifoliate leaves and blue-violet flowers grown widely as a pasture and hay crop

Other synonyms of Medicago sativa include lucerne.

Medicago sativa (noun)	alfalfa (noun)
important European leguminous forage plant with trifoliate leaves and blue-violet flowers grown widely as a pasture and hay crop	leguminous plant grown for hay or forage
	important European leguminous forage plant with trifoliate leaves and blue-violet flowers grown widely as a pasture and hay crop