1 a a sovereign's or State's territory; a domain. b land attached to a mansion etc. c landed property; an estate.
2 (usu. foll. by of) a region or sphere.
3 Law hist. possession (of real property) as one's own.
Phrases and idioms:
held in demesne (of an estate) occupied by the owner, not by tenants.
Etymology: ME f. AF, OF demeine (later AF demesne) belonging to a lord f. L dominicus (as DOMINICAL)
Useful english dictionary. 2012.