immovable vs demesne

immovable and demesne both are nouns.

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

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

immovable: property consisting of houses and land
demesne: extensive landed property (especially in the country) retained by the owner for his own use

Other hyponyms of immovable include acres, estate, land, landed estate, land, dead hand, mortmain.

immovable (noun)	demesne (noun)
property consisting of houses and land	territory over which rule or control is exercised
	extensive landed property (especially in the country) retained by the owner for his own use

immovable (adjective)	demesne (adjective)
not able or intended to be moved