princess vs archduchess

princess and archduchess both are nouns.

Word	Noun	Adjective	Verb	Adverb
princess	Yes	No	No	No
archduchess	Yes	No	No	No

As nouns, archduchess is a hyponym of princess; that is, archduchess is a word with a more specific, narrower meaning than princess:

princess: a female member of a royal family other than the queen (especially the daughter of a sovereign)
archduchess: a wife or widow of an archduke or a princess of the former ruling house of Austria

Other hyponyms of princess include crown princess, maharanee, maharani, princess royal.

princess (noun)	archduchess (noun)
a female member of a royal family other than the queen (especially the daughter of a sovereign)	a wife or widow of an archduke or a princess of the former ruling house of Austria