viscounty vs demesne

viscounty and demesne both are nouns.

Word	Noun	Adjective	Verb	Adverb
viscounty	Yes	No	No	No
demesne	Yes	No	No	No

As nouns, demesne is a hypernym of viscounty; that is, demesne is a word with a broader meaning than viscounty:

Other hypernyms of viscounty include domain, land.

viscounty (noun)	demesne (noun)
the domain controlled by a viscount or viscountess	territory over which rule or control is exercised
the dignity or rank or position of a viscount or viscountess	extensive landed property (especially in the country) retained by the owner for his own use