Seville orange vs Seville orange

Seville orange and Seville orange both are nouns.

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

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