Citrus aurantium vs bitter orange tree

Citrus aurantium and bitter orange tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
Citrus aurantium	Yes	No	No	No
bitter orange tree	Yes	No	No	No

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

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

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

Citrus aurantium (noun)	bitter orange tree (noun)
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