Crown land vs demesne

Crown land and demesne both are nouns.

Word	Noun	Adjective	Verb	Adverb
Crown land	Yes	No	No	No
demesne	Yes	No	No	No

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

Crown land: land that belongs to the Crown
demesne: extensive landed property (especially in the country) retained by the owner for his own use

Other hypernyms of Crown land include acres, estate, land, landed estate.

Crown land (noun)	demesne (noun)
land that belongs to the Crown	territory over which rule or control is exercised
	extensive landed property (especially in the country) retained by the owner for his own use