One word substitute is Bungalow.Bungalow: a low house having only one storey or, in some cases, upper rooms set in the roof, typically with dormer windows.Cottage: a small house, typically one in the country.Flat: having a level surface; without raised areas or indentations.Castle: a large building, typically of the medieval period, fortified against attack with thick walls, battlements, towers, and in many cases a moat.