What does "chateau" mean?

Chateau: A manor house or residence of the lord of the manor; a gentleman's country seat; also, particularly, a royal residence; as, the chateau of the Louvre; the chateau of the Luxembourg. Note: The distinctive, French term for a fortified caste of the middle ages is château-fort. Chateau en Espagne ( Etym: [F.], a castle in Spain, that is, a castle in the air, Spain being the region of romance.