viscountess vs wife

viscountess and wife both are nouns.

Word	Noun	Adjective	Verb	Adverb
viscountess	Yes	No	No	No
wife	Yes	No	No	No

As nouns, wife is a hypernym of viscountess; that is, wife is a word with a broader meaning than viscountess:

Other hypernyms of viscountess include married woman.

viscountess (noun)	wife (noun)
a noblewoman holding the rank of viscount in her own right	a married woman; a man's partner in marriage
a wife or widow of a viscount