Citrus aurantium vs Seville orange

Citrus aurantium and Seville orange both are nouns.

Word	Noun	Adjective	Verb	Adverb
Citrus aurantium	Yes	No	No	No
Seville orange	Yes	No	No	No

As nouns, Citrus aurantium and Seville orange are synonyms defined as:

Citrus aurantium and Seville orange: any of various common orange trees yielding sour or bitter fruit; used as grafting stock

Other synonyms of Citrus aurantium include bigarade, bitter orange, bitter orange tree, marmalade orange, sour orange.

Citrus aurantium (noun)	Seville orange (noun)
any of various common orange trees yielding sour or bitter fruit; used as grafting stock	highly acidic orange used especially in marmalade
	any of various common orange trees yielding sour or bitter fruit; used as grafting stock