sour orange vs bitter orange tree

sour orange and bitter orange tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
sour orange	Yes	No	No	No
bitter orange tree	Yes	No	No	No

As nouns, sour orange and bitter orange tree are synonyms defined as:

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

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

sour orange (noun)	bitter orange tree (noun)
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