A manor is the house of a lord — pretty fancy stuff. If you like to read 18th-century British novels, you probably read about a lot of people having dinner, dance, and restrained romance in their manors.
Manor comes from the Old French manoir, meaning "dwelling place," but a manor isn't just any old dwelling place. In the days when people still had titles of nobility, the houses and the grounds of the nobles were known as manors. If you tell someone that his house is a manor, that's like saying it's so opulent and lovely that it could have belonged to a lord.