Catholic Monarchs vs Ferdinand and Isabella

Catholic Monarchs and Ferdinand and Isabella both are nouns.

Word	Noun	Adjective	Verb	Adverb
Catholic Monarchs	Yes	No	No	No
Ferdinand and Isabella	Yes	No	No	No

As nouns, Catholic Monarchs and Ferdinand and Isabella are synonyms defined as:

Catholic Monarchs and Ferdinand and Isabella: joint monarchs of Spain; Ferdinand V and Isabella I

Catholic Monarchs (noun)	Ferdinand and Isabella (noun)
joint monarchs of Spain; Ferdinand V and Isabella I	joint monarchs of Spain; Ferdinand V and Isabella I