Bishop of Rome vs Catholic Pope

Bishop of Rome and Catholic Pope both are nouns.

Word	Noun	Adjective	Verb	Adverb
Bishop of Rome	Yes	No	No	No
Catholic Pope	Yes	No	No	No

As nouns, Bishop of Rome and Catholic Pope are synonyms defined as:

Other synonyms of Bishop of Rome include Holy Father, pontiff, pope, Roman Catholic Pope, Vicar of Christ.

Bishop of Rome (noun)	Catholic Pope (noun)
the head of the Roman Catholic Church	the head of the Roman Catholic Church